Provided by: zsh-common_5.8.1-1_all bug

NAME

       zshcompsys - zsh completion system

DESCRIPTION

       This  describes the shell code for the `new' completion system, referred to as compsys.  It is written in
       shell functions based on the features described in zshcompwid(1).

       The features are contextual, sensitive to the point at which completion is started.  Many completions are
       already provided.  For this reason, a user can perform a great many tasks  without  knowing  any  details
       beyond how to initialize the system, which is described below in INITIALIZATION.

       The context that decides what completion is to be performed may be
       •      an  argument  or  option  position:  these  describe  the  position  on  the command line at which
              completion is requested.  For example `first argument to rmdir, the word being completed  names  a
              directory';

       •      a  special  context,  denoting  an  element in the shell's syntax.  For example `a word in command
              position' or `an array subscript'.

       A full context specification contains other elements, as we shall describe.

       Besides commands names and contexts, the system employs  two  more  concepts,  styles  and  tags.   These
       provide ways for the user to configure the system's behaviour.

       Tags  play  a  dual  role.  They serve as a classification system for the matches, typically indicating a
       class of object that the user may need to distinguish.  For example, when completing arguments of the  ls
       command the user may prefer to try files before directories, so both of these are tags.  They also appear
       as the rightmost element in a context specification.

       Styles modify various operations of the completion system, such as output formatting, but also what kinds
       of  completers are used (and in what order), or which tags are examined.  Styles may accept arguments and
       are manipulated using the zstyle command described in see zshmodules(1).

       In summary, tags describe what the completion objects are, and style how they are to  be  completed.   At
       various  points  of  execution,  the completion system checks what styles and/or tags are defined for the
       current context, and uses that to modify its behavior.  The full description of context  handling,  which
       determines  how  tags  and  other elements of the context influence the behaviour of styles, is described
       below in COMPLETION SYSTEM CONFIGURATION.

       When a completion is requested, a dispatcher function is called; see the description of _main_complete in
       the list of control functions below. This dispatcher decides which function should be called  to  produce
       the  completions,  and calls it. The result is passed to one or more completers, functions that implement
       individual completion strategies: simple completion, error correction, completion with error  correction,
       menu selection, etc.

       More generally, the shell functions contained in the completion system are of two types:
       •      those beginning `comp' are to be called directly; there are only a few of these;

       •      those  beginning  `_'  are  called by the completion code.  The shell functions of this set, which
              implement completion behaviour and may be bound to  keystrokes,  are  referred  to  as  `widgets'.
              These proliferate as new completions are required.

INITIALIZATION

       If the system was installed completely, it should be enough to call the shell function compinit from your
       initialization  file;  see  the  next section.  However, the function compinstall can be run by a user to
       configure various aspects of the completion system.

       Usually, compinstall will insert code into .zshrc, although if that is not writable it will  save  it  in
       another  file  and  tell you that file's location.  Note that it is up to you to make sure that the lines
       added to .zshrc are actually run; you may, for example, need to move them to an earlier place in the file
       if .zshrc usually returns early.  So long as you keep them all together (including the comment  lines  at
       the  start  and  finish),  you can rerun compinstall and it will correctly locate and modify these lines.
       Note, however, that any code you add to this  section  by  hand  is  likely  to  be  lost  if  you  rerun
       compinstall, although lines using the command `zstyle' should be gracefully handled.

       The  new  code  will  take  effect next time you start the shell, or run .zshrc by hand; there is also an
       option to make them take effect immediately.  However, if compinstall has removed definitions,  you  will
       need to restart the shell to see the changes.

       To  run  compinstall  you  will need to make sure it is in a directory mentioned in your fpath parameter,
       which should already be the case if zsh was properly configured as long as  your  startup  files  do  not
       remove  the appropriate directories from fpath.  Then it must be autoloaded (`autoload -U compinstall' is
       recommended).  You can abort the installation any time you are being prompted for information,  and  your
       .zshrc  will  not be altered at all; changes only take place right at the end, where you are specifically
       asked for confirmation.

   Use of compinit
       This section describes the use of compinit to initialize completion for the current session  when  called
       directly; if you have run compinstall it will be called automatically from your .zshrc.

       To  initialize  the  system,  the  function  compinit  should  be  in  a directory mentioned in the fpath
       parameter, and should be autoloaded (`autoload -U compinit' is  recommended),  and  then  run  simply  as
       `compinit'.   This  will define a few utility functions, arrange for all the necessary shell functions to
       be autoloaded, and will then re-define all widgets that do completion to use the new system.  If you  use
       the  menu-select  widget, which is part of the zsh/complist module, you should make sure that that module
       is loaded before the call to compinit so that that widget is also re-defined.  If completion styles  (see
       below)  are  set  up  to  perform expansion as well as completion by default, and the TAB key is bound to
       expand-or-complete, compinit will rebind it to complete-word; this is necessary to use the  correct  form
       of expansion.

       Should  you  need  to use the original completion commands, you can still bind keys to the old widgets by
       putting a `.' in front of the widget name, e.g. `.expand-or-complete'.

       To speed up the running of compinit, it can be made to produce a dumped configuration that will  be  read
       in  on future invocations; this is the default, but can be turned off by calling compinit with the option
       -D.  The dumped file is .zcompdump in the same directory as the startup files (i.e. $ZDOTDIR  or  $HOME);
       alternatively,  an  explicit  file  name  can be given by `compinit -d dumpfile'.  The next invocation of
       compinit will read the dumped file instead of performing a full initialization.

       If the number of completion files changes, compinit will recognise this and  produce  a  new  dump  file.
       However,  if  the  name  of  a  function  or  the  arguments in the first line of a #compdef function (as
       described below) change, it is easiest to delete the dump file by hand so that compinit will re-create it
       the next time it is run.  The check performed to see if there are new functions can be omitted by  giving
       the option -C.  In this case the dump file will only be created if there isn't one already.

       The  dumping  is actually done by another function, compdump, but you will only need to run this yourself
       if you change the configuration (e.g. using compdef) and then want to dump the new one.  The name of  the
       old dumped file will be remembered for this purpose.

       If  the  parameter  _compdir  is  set,  compinit uses it as a directory where completion functions can be
       found; this is only necessary if they are not already in the function search path.

       For security reasons compinit also checks if the completion system would use files not owned by  root  or
       by  the  current user, or files in directories that are world- or group-writable or that are not owned by
       root or by the current user.  If such files or directories are found, compinit will ask if the completion
       system should really be used.  To avoid these tests and make all files found be used without asking,  use
       the option -u, and to make compinit silently ignore all insecure files and directories use the option -i.
       This security check is skipped entirely when the -C option is given.

       The  security check can be retried at any time by running the function compaudit.  This is the same check
       used by compinit, but when it is executed directly any changes to fpath are made local to the function so
       they do not persist.  The directories to be checked may be  passed  as  arguments;  if  none  are  given,
       compaudit  uses fpath and _compdir to find completion system directories, adding missing ones to fpath as
       necessary.  To force a check of exactly the directories currently named in  fpath,  set  _compdir  to  an
       empty string before calling compaudit or compinit.

       The function bashcompinit provides compatibility with bash's programmable completion system.  When run it
       will  define  the  functions,  compgen  and  complete which correspond to the bash builtins with the same
       names.  It will then be possible to use completion specifications and functions written for bash.

   Autoloaded files
       The convention for autoloaded functions used in completion is that they  start  with  an  underscore;  as
       already mentioned, the fpath/FPATH parameter must contain the directory in which they are stored.  If zsh
       was  properly  installed on your system, then fpath/FPATH automatically contains the required directories
       for the standard functions.

       For incomplete installations, if compinit does not find enough files beginning with an underscore  (fewer
       than  twenty) in the search path, it will try to find more by adding the directory _compdir to the search
       path.  If that directory has a subdirectory named Base, all subdirectories will be  added  to  the  path.
       Furthermore, if the subdirectory Base has a subdirectory named Core, compinit will add all subdirectories
       of  the  subdirectories  to  the  path:  this allows the functions to be in the same format as in the zsh
       source distribution.

       When compinit is run, it searches all such files accessible via fpath/FPATH and reads the first  line  of
       each of them.  This line should contain one of the tags described below.  Files whose first line does not
       start  with  one  of  these  tags  are not considered to be part of the completion system and will not be
       treated specially.

       The tags are:

       #compdef name ... [ -{p|P} pattern ... [ -N name ... ] ]
              The file will be made autoloadable and the function defined in it will be called  when  completing
              names, each of which is either the name of a command whose arguments are to be completed or one of
              a number of special contexts in the form -context- described below.

              Each  name  may  also be of the form `cmd=service'.  When completing the command cmd, the function
              typically behaves as if the command (or special context)  service  was  being  completed  instead.
              This  provides  a  way  of  altering  the  behaviour  of functions that can perform many different
              completions.  It is implemented by setting the parameter $service when calling the  function;  the
              function  may  choose  to interpret this how it wishes, and simpler functions will probably ignore
              it.

              If the #compdef line contains one of the options -p or -P, the words following  are  taken  to  be
              patterns.   The function will be called when completion is attempted for a command or context that
              matches one of the patterns.  The options -p and -P are used  to  specify  patterns  to  be  tried
              before or after other completions respectively.  Hence -P may be used to specify default actions.

              The option -N is used after a list following -p or -P; it specifies that remaining words no longer
              define patterns.  It is possible to toggle between the three options as many times as necessary.

       #compdef -k style key-sequence ...
              This  option  creates  a  widget  behaving like the builtin widget style and binds it to the given
              key-sequences, if any.  The style must be one of the  builtin  widgets  that  perform  completion,
              namely    complete-word,   delete-char-or-list,   expand-or-complete,   expand-or-complete-prefix,
              list-choices,  menu-complete,   menu-expand-or-complete,   or   reverse-menu-complete.    If   the
              zsh/complist module is loaded (see zshmodules(1)) the widget menu-select is also available.

              When  one  of the key-sequences is typed, the function in the file will be invoked to generate the
              matches.  Note that a key will not be re-bound if it already was (that is, was bound to  something
              other  than  undefined-key).  The widget created has the same name as the file and can be bound to
              any other keys using bindkey as usual.

       #compdef -K widget-name style key-sequence [ name style seq ... ]
              This is similar to -k except that only one key-sequence argument may be given for each widget-name
              style pair.  However, the entire set of three arguments may be repeated with a  different  set  of
              arguments.   Note in particular that the widget-name must be distinct in each set.  If it does not
              begin with `_' this will be added.  The widget-name should not clash with the name of any existing
              widget: names based on the name of the function are most useful.  For example,

                     #compdef -K _foo_complete complete-word "^X^C" \
                       _foo_list list-choices "^X^D"

              (all on one line) defines a widget _foo_complete for completion, bound to  `^X^C',  and  a  widget
              _foo_list for listing, bound to `^X^D'.

       #autoload [ options ]
              Functions  with  the  #autoload  tag  are  marked  for  autoloading  but are not otherwise treated
              specially.  Typically they are to be called from within one  of  the  completion  functions.   Any
              options supplied will be passed to the autoload builtin; a typical use is +X to force the function
              to be loaded immediately.  Note that the -U and -z flags are always added implicitly.

       The  # is part of the tag name and no white space is allowed after it.  The #compdef tags use the compdef
       function described below; the main difference is that the name of the function is supplied implicitly.

       The special contexts for which completion functions can be defined are:

       -array-value-
              The right hand side of an array-assignment (`name=(...)')

       -brace-parameter-
              The name of a parameter expansion within braces (`${...}')

       -assign-parameter-
              The name of a parameter in an assignment, i.e. on the left hand side of an `='

       -command-
              A word in command position

       -condition-
              A word inside a condition (`[[...]]')

       -default-
              Any word for which no other completion is defined

       -equal-
              A word beginning with an equals sign

       -first-
              This is tried before any other completion function.  The function called  may  set  the  _compskip
              parameter  to  one of various values: all: no further completion is attempted; a string containing
              the substring patterns: no pattern completion  functions  will  be  called;  a  string  containing
              default:  the  function  for the `-default-' context will not be called, but functions defined for
              commands will be.

       -math- Inside mathematical contexts, such as `((...))'

       -parameter-
              The name of a parameter expansion (`$...')

       -redirect-
              The word after a redirection operator.

       -subscript-
              The contents of a parameter subscript.

       -tilde-
              After an initial tilde (`~'), but before the first slash in the word.

       -value-
              On the right hand side of an assignment.

       Default implementations are supplied for each of these contexts.  In most cases the context -context-  is
       implemented  by  a  corresponding  function  _context, for example the context `-tilde-' and the function
       `_tilde').

       The contexts -redirect- and -value- allow  extra  context-specific  information.   (Internally,  this  is
       handled  by  the  functions  for  each context calling the function _dispatch.)  The extra information is
       added separated by commas.

       For the -redirect- context, the extra information is in the form `-redirect-,op,command', where op is the
       redirection operator and command is the name of the command on the line.  If there is no command  on  the
       line yet, the command field will be empty.

       For  the  -value- context, the form is `-value-,name,command', where name is the name of the parameter on
       the left hand side of the assignment.  In the case of elements  of  an  associative  array,  for  example
       `assoc=(key  <TAB>',  name  is  expanded  to `name-key'.  In certain special contexts, such as completing
       after `make CFLAGS=', the command part gives the name of the command, here make; otherwise it is empty.

       It is not necessary to define fully specific completions as the functions provided will try  to  generate
       completions by progressively replacing the elements with `-default-'.  For example, when completing after
       `foo=<TAB>',   _value   will   try   the   names   `-value-,foo,'   (note   the   empty   command  part),
       `-value-,foo,-default-' and`-value-,-default-,-default-', in that order, until it  finds  a  function  to
       handle the context.

       As an example:

              compdef '_files -g "*.log"' '-redirect-,2>,-default-'

       completes files matching `*.log' after `2> <TAB>' for any command with no more specific handler defined.

       Also:


              compdef _foo -value-,-default-,-default-
       specifies  that  _foo provides completions for the values of parameters for which no special function has
       been defined.  This is usually handled by the function _value itself.

       The same lookup rules are used when looking up styles (as described below); for example

              zstyle ':completion:*:*:-redirect-,2>,*:*' file-patterns '*.log'

       is another way to make completion after `2> <TAB>' complete files matching `*.log'.

   Functions
       The following function is defined by compinit and may be called directly.

       compdef [ -ane ] function name ... [ -{p|P} pattern ... [ -N name ...]]
       compdef -d name ...
       compdef -k [ -an ] function style key-sequence [ key-sequence ... ]
       compdef -K [ -an ] function name style key-seq [ name style seq ... ]
              The first form defines the function to call for completion in the given contexts as described  for
              the #compdef tag above.

              Alternatively,  all  the  arguments  may have the form `cmd=service'.  Here service should already
              have been defined by `cmd1=service' lines in #compdef files, as described above.  The argument for
              cmd will be completed in the same way as service.

              The function argument may alternatively be a string containing almost  any  shell  code.   If  the
              string  contains  an  equal  sign,  the  above will take precedence.  The option -e may be used to
              specify the first argument is to be evaluated as shell code even if it  contains  an  equal  sign.
              The string will be executed using the eval builtin command to generate completions.  This provides
              a  way  of  avoiding  having  to define a new completion function.  For example, to complete files
              ending in `.h' as arguments to the command foo:

                     compdef '_files -g "*.h"' foo

              The option -n prevents any completions already defined for  the  command  or  context  from  being
              overwritten.

              The option -d deletes any completion defined for the command or contexts listed.

              The names may also contain -p, -P and -N options as described for the #compdef tag.  The effect on
              the  argument  list  is  identical,  switching  between  definitions  of patterns tried initially,
              patterns tried finally, and normal commands and contexts.

              The parameter $_compskip may be set by any function defined for a pattern context.  If it  is  set
              to a value containing the substring `patterns' none of the pattern-functions will be called; if it
              is  set  to  a  value  containing  the substring `all', no other function will be called.  Setting
              $_compskip in this manner is of particular utility when using the  -p  option,  as  otherwise  the
              dispatcher  will  move  on  to  additional  functions  (likely  the default one) after calling the
              pattern-context one, which can mangle the display  of  completion  possibilities  if  not  handled
              properly.

              The  form with -k defines a widget with the same name as the function that will be called for each
              of the key-sequences; this is like  the  #compdef  -k  tag.   The  function  should  generate  the
              completions  needed  and  will otherwise behave like the builtin widget whose name is given as the
              style  argument.   The  widgets  usable  for   this   are:   complete-word,   delete-char-or-list,
              expand-or-complete,         expand-or-complete-prefix,         list-choices,        menu-complete,
              menu-expand-or-complete, and reverse-menu-complete, as well as  menu-select  if  the  zsh/complist
              module  is  loaded.   The  option  -n  prevents  the  key being bound if it is already to bound to
              something other than undefined-key.

              The form with -K is similar and defines multiple widgets based on the same function, each of which
              requires the set of three arguments name, style and key-sequence, where the latter two are as  for
              -k and the first must be a unique widget name beginning with an underscore.

              Wherever  applicable,  the  -a  option  makes the function autoloadable, equivalent to autoload -U
              function.

       The function compdef can be used to associate existing  completion  functions  with  new  commands.   For
       example,

              compdef _pids foo

       uses the function _pids to complete process IDs for the command foo.

       Note  also  the _gnu_generic function described below, which can be used to complete options for commands
       that understand the `--help' option.

COMPLETION SYSTEM CONFIGURATION

       This section gives a short overview of how the completion system works, and then more detail on how users
       can configure how and when matches are generated.

   Overview
       When completion is attempted somewhere on the command line the  completion  system  begins  building  the
       context.   The  context  represents everything that the shell knows about the meaning of the command line
       and the significance of the cursor position.  This takes account of a  number  of  things  including  the
       command  word (such as `grep' or `zsh') and options to which the current word may be an argument (such as
       the `-o' option to zsh which takes a shell option as an argument).

       The context starts out very generic ("we are beginning a completion") and becomes more specific  as  more
       is learned ("the current word is in a position that is usually a command name" or "the current word might
       be  a  variable name" and so on).  Therefore the context will vary during the same call to the completion
       system.

       This context information is condensed into a string consisting of multiple fields  separated  by  colons,
       referred  to  simply  as  `the  context'  in the remainder of the documentation.  Note that a user of the
       completion system rarely needs to compose a context string, unless for example a new  function  is  being
       written  to perform completion for a new command.  What a user may need to do is compose a style pattern,
       which is matched against a context when needed to look up context-sensitive options  that  configure  the
       completion system.

       The  next  few  paragraphs  explain  how  a  context  is  composed  within the completion function suite.
       Following that is discussion of how styles are defined.  Styles determine such things as how the  matches
       are  generated,  similarly to shell options but with much more control.  They are defined with the zstyle
       builtin command (see zshmodules(1)).

       The context string always consists of a fixed set of fields, separated by colons and with a leading colon
       before the first.  Fields which are not yet known are left  empty,  but  the  surrounding  colons  appear
       anyway.   The  fields are always in the order :completion:function:completer:command:argument:tag.  These
       have the following meaning:

       •      The literal string completion, saying that this style is used  by  the  completion  system.   This
              distinguishes the context from those used by, for example, zle widgets and ZFTP functions.

       •      The  function,  if  completion  is  called  from  a  named  widget  rather than through the normal
              completion system.  Typically this is blank, but it is set by special widgets such  as  predict-on
              and  the  various  functions  in  the  Widget  directory  of  the distribution to the name of that
              function, often in an abbreviated form.

       •      The completer currently active, the name of the function without the leading underscore  and  with
              other  underscores converted to hyphens.  A `completer' is in overall control of how completion is
              to be performed; `complete' is the simplest, but other completers exist to perform  related  tasks
              such  as  correction,  or  to modify the behaviour of a later completer.  See the section `Control
              Functions' below for more information.

       •      The command or a special -context-, just at it appears following the #compdef tag or  the  compdef
              function.   Completion  functions for commands that have sub-commands usually modify this field to
              contain the name of the command followed by a minus sign and the sub-command.   For  example,  the
              completion  function  for  the cvs command sets this field to cvs-add when completing arguments to
              the add subcommand.

       •      The argument; this indicates which command line or option argument we are completing.  For command
              arguments this generally takes the form argument-n, where n is the number of the argument, and for
              arguments to options the form option-opt-n where n is the number of the argument  to  option  opt.
              However,  this is only the case if the command line is parsed with standard UNIX-style options and
              arguments, so many completions do not set this.

       •      The tag.  As described previously, tags are used to discriminate between the types  of  matches  a
              completion  function  can  generate in a certain context.  Any completion function may use any tag
              name it likes, but a list of the more common ones is given below.

       The context is gradually put together as the functions are executed, starting with the main entry  point,
       which  adds  :completion:  and  the function element if necessary.  The completer then adds the completer
       element.  The contextual completion adds the command and argument options.  Finally,  the  tag  is  added
       when the types of completion are known.  For example, the context name

              :completion::complete:dvips:option-o-1:files

       says that normal completion was attempted as the first argument to the option -o of the command dvips:

              dvips -o ...

       and the completion function will generate filenames.

       Usually  completion  will  be  tried  for all possible tags in an order given by the completion function.
       However, this can be altered by using the tag-order style.  Completion is then restricted to the list  of
       given tags in the given order.

       The  _complete_help  bindable  command  shows  all  the  contexts  and tags available for completion at a
       particular point.  This provides an easy way of finding information for tag-order and other  styles.   It
       is described in the section `Bindable Commands' below.

       When  looking up styles the completion system uses full context names, including the tag.  Looking up the
       value of a style therefore consists of two things: the context, which is matched  to  the  most  specific
       (best  fitting)  style  pattern,  and  the  name of the style itself, which must be matched exactly.  The
       following examples demonstrate that style patterns may be loosely defined for styles that apply  broadly,
       or as tightly defined as desired for styles that apply in narrower circumstances.

       For  example,  many  completion functions can generate matches in a simple and a verbose form and use the
       verbose style to decide which form should be used.  To make all such functions use the verbose form, put

              zstyle ':completion:*' verbose yes

       in a startup file (probably .zshrc).  This gives the verbose style the value yes in every context  inside
       the  completion  system,  unless that context has a more specific definition.  It is best to avoid giving
       the context as `*' in case the style has some meaning outside the completion system.

       Many such general purpose styles can be configured simply by using the compinstall function.

       A more specific example of the use of the verbose style is by the completion for the  kill  builtin.   If
       the style is set, the builtin lists full job texts and process command lines; otherwise it shows the bare
       job numbers and PIDs.  To turn the style off for this use only:

              zstyle ':completion:*:*:kill:*:*' verbose no

       For  even  more  control,  the  style can use one of the tags `jobs' or `processes'.  To turn off verbose
       display only for jobs:

              zstyle ':completion:*:*:kill:*:jobs' verbose no

       The -e option to zstyle even allows completion function code to appear as the argument to a  style;  this
       requires  some  understanding  of  the  internals  of completion functions (see see zshcompwid(1))).  For
       example,

              zstyle -e ':completion:*' hosts 'reply=($myhosts)'

       This forces the value of the hosts style to be read from the variable myhosts each time a  host  name  is
       needed;  this  is useful if the value of myhosts can change dynamically.  For another useful example, see
       the example in the description of the file-list style below.  This form can be slow and should be avoided
       for commonly examined styles such as menu and list-rows-first.

       Note that the order in which styles are defined does not  matter;  the  style  mechanism  uses  the  most
       specific  possible  match for a particular style to determine the set of values.  More precisely, strings
       are  preferred  over  patterns  (for  example,  `:completion::complete:::foo'  is  more   specific   than
       `:completion::complete:::*'), and longer patterns are preferred over shorter patterns.

       A  good  rule  of thumb is that any completion style pattern that needs to include more than one wildcard
       (*) and that does not end in a tag  name,  should  include  all  six  colons  (:),  possibly  surrounding
       additional wildcards.

       Style  names  like  those  of  tags  are  arbitrary  and depend on the completion function.  However, the
       following two sections list some of the most common tags and styles.

   Standard Tags
       Some of the following are only used when looking up particular styles and do  not  refer  to  a  type  of
       match.

       accounts
              used to look up the users-hosts style

       all-expansions
              used by the _expand completer when adding the single string containing all possible expansions

       all-files
              for the names of all files (as distinct from a particular subset, see the globbed-files tag).

       arguments
              for arguments to a command

       arrays for names of array parameters

       association-keys
              for  keys  of  associative  arrays; used when completing inside a subscript to a parameter of this
              type

       bookmarks
              when completing bookmarks (e.g. for URLs and the zftp function suite)

       builtins
              for names of builtin commands

       characters
              for single characters in arguments of commands such as stty.   Also used when completing character
              classes after an opening bracket

       colormapids
              for X colormap ids

       colors for color names

       commands
              for names of external commands.  Also used by complex commands such as cvs when  completing  names
              subcommands.

       contexts
              for contexts in arguments to the zstyle builtin command

       corrections
              used by the _approximate and _correct completers for possible corrections

       cursors
              for cursor names used by X programs

       default
              used  in  some  contexts  to provide a way of supplying a default when more specific tags are also
              valid.  Note that this tag is used when only the function field of the context name is set

       descriptions
              used when looking up the value of the format style to generate descriptions for types of matches

       devices
              for names of device special files

       directories
              for names of directories -- local-directories is used instead when completing arguments of cd  and
              related builtin commands when the cdpath array is set

       directory-stack
              for entries in the directory stack

       displays
              for X display names

       domains
              for network domains

       email-plugin
              for email addresses from the `_email-plugin' backend of _email_addresses

       expansions
              used  by the _expand completer for individual words (as opposed to the complete set of expansions)
              resulting from the expansion of a word on the command line

       extensions
              for X server extensions

       file-descriptors
              for numbers of open file descriptors

       files  the generic file-matching tag used by functions completing filenames

       fonts  for X font names

       fstypes
              for file system types (e.g. for the mount command)

       functions
              names of functions -- normally shell functions, although certain  commands  may  understand  other
              kinds of function

       globbed-files
              for filenames when the name has been generated by pattern matching

       groups for names of user groups

       history-words
              for words from the history

       hosts  for hostnames

       indexes
              for array indexes

       jobs   for jobs (as listed by the `jobs' builtin)

       interfaces
              for network interfaces

       keymaps
              for names of zsh keymaps

       keysyms
              for names of X keysyms

       libraries
              for names of system libraries

       limits for system limits

       local-directories
              for  names of directories that are subdirectories of the current working directory when completing
              arguments of cd and related builtin commands (compare path-directories) -- when the  cdpath  array
              is unset, directories is used instead

       manuals
              for names of manual pages

       mailboxes
              for e-mail folders

       maps   for map names (e.g. NIS maps)

       messages
              used to look up the format style for messages

       modifiers
              for names of X modifiers

       modules
              for modules (e.g. zsh modules)

       my-accounts
              used to look up the users-hosts style

       named-directories
              for named directories (you wouldn't have guessed that, would you?)

       names  for all kinds of names

       newsgroups
              for USENET groups

       nicknames
              for nicknames of NIS maps

       options
              for command options

       original
              used  by  the _approximate, _correct and _expand completers when offering the original string as a
              match

       other-accounts
              used to look up the users-hosts style

       other-files
              for the  names  of  any  non-directory  files.   This  is  used  instead  of  all-files  when  the
              list-dirs-first style is in effect.

       packages
              for packages (e.g. rpm or installed Debian packages)

       parameters
              for names of parameters

       path-directories
              for  names  of directories found by searching the cdpath array when completing arguments of cd and
              related builtin commands (compare local-directories)

       paths  used to look up the values of the expand, ambiguous and special-dirs styles

       pods   for perl pods (documentation files)

       ports  for communication ports

       prefixes
              for prefixes (like those of a URL)

       printers
              for print queue names

       processes
              for process identifiers

       processes-names
              used to look up the command style when generating the names of processes for killall

       sequences
              for sequences (e.g. mh sequences)

       sessions
              for sessions in the zftp function suite

       signals
              for signal names

       strings
              for strings (e.g. the replacement strings for the cd builtin command)

       styles for styles used by the zstyle builtin command

       suffixes
              for filename extensions

       tags   for tags (e.g. rpm tags)

       targets
              for makefile targets

       time-zones
              for time zones (e.g. when setting the TZ parameter)

       types  for types of whatever (e.g. address types for the xhost command)

       urls   used to look up the urls and local styles when completing URLs

       users  for usernames

       values for one of a set of values in certain lists

       variant
              used by _pick_variant to look up the command to run when determining what program is installed for
              a particular command name.

       visuals
              for X visuals

       warnings
              used to look up the format style for warnings

       widgets
              for zsh widget names

       windows
              for IDs of X windows

       zsh-options
              for shell options

   Standard Styles
       Note that the values of several of these styles represent boolean values.  Any  of  the  strings  `true',
       `on',  `yes',  and  `1' can be used for the value `true' and any of the strings `false', `off', `no', and
       `0' for the value `false'.  The behavior for  any  other  value  is  undefined  except  where  explicitly
       mentioned.  The default value may be either `true' or `false' if the style is not set.

       Some  of these styles are tested first for every possible tag corresponding to a type of match, and if no
       style was found, for the default tag.  The most notable styles of this type  are  menu,  list-colors  and
       styles  controlling  completion listing such as list-packed and last-prompt.  When tested for the default
       tag, only the function field of the context will be set so that  a  style  using  the  default  tag  will
       normally be defined along the lines of:

              zstyle ':completion:*:default' menu ...

       accept-exact
              This  is  tested for the default tag in addition to the tags valid for the current context.  If it
              is set to `true' and any of the trial matches is the same as the string on the command line,  this
              match will immediately be accepted (even if it would otherwise be considered ambiguous).

              When  completing  pathnames  (where  the  tag  used  is  `paths') this style accepts any number of
              patterns as the value in addition to the boolean values.  Pathnames matching one of these patterns
              will be accepted immediately even if the command line contains some more partially typed  pathname
              components and these match no file under the directory accepted.

              This  style  is  also  used  by the _expand completer to decide if words beginning with a tilde or
              parameter expansion should be expanded.  For example, if there are parameters foo and foobar,  the
              string  `$foo'  will  only  be expanded if accept-exact is set to `true'; otherwise the completion
              system will be allowed to complete $foo to $foobar. If the style is  set  to  `continue',  _expand
              will add the expansion as a match and the completion system will also be allowed to continue.

       accept-exact-dirs
              This  is  used by filename completion.  Unlike accept-exact it is a boolean.  By default, filename
              completion examines all components of a path to see if there are completions  of  that  component,
              even  if  the  component  matches  an  existing  directory.   For  example,  when completion after
              /usr/bin/, the function examines possible completions to /usr.

              When this style is `true', any prefix of a path that matches an  existing  directory  is  accepted
              without  any  attempt  to complete it further.  Hence, in the given example, the path /usr/bin/ is
              accepted immediately and completion tried in that directory.

              This style is also useful when completing after directories that magically appear when referenced,
              such as ZFS .zfs directories or NetApp .snapshot directories.  When the style  is  set  the  shell
              does not check for the existence of the directory within the parent directory.

              If  you  wish  to  inhibit  this  behaviour entirely, set the path-completion style (see below) to
              `false'.

       add-space
              This style is used by the _expand completer.  If it is `true'  (the  default),  a  space  will  be
              inserted  after all words resulting from the expansion, or a slash in the case of directory names.
              If the value is `file', the completer will only add a space to names of existing files.  Either  a
              boolean  `true' or the value `file' may be combined with `subst', in which case the completer will
              not add a space to words generated from the expansion of a substitution of the  form  `$(...)'  or
              `${...}'.

              The  _prefix  completer  uses  this style as a simple boolean value to decide if a space should be
              inserted before the suffix.

       ambiguous
              This applies when completing non-final components of filename paths, in other words those  with  a
              trailing  slash.   If  it  is set, the cursor is left after the first ambiguous component, even if
              menu completion is in use.  The style is always tested with the paths tag.

       assign-list
              When completing after an equals sign that is being treated as an assignment, the completion system
              normally completes only one filename.  In some cases  the  value   may  be  a  list  of  filenames
              separated  by  colons,  as  with  PATH and similar parameters.  This style can be set to a list of
              patterns matching the names of such parameters.

              The default is to complete lists when the word on the line already contains a colon.

       auto-description
              If set, this style's value will be used as the description for options that are not  described  by
              the completion functions, but that have exactly one argument.  The sequence `%d' in the value will
              be  replaced  by  the description for this argument.  Depending on personal preferences, it may be
              useful to set this style to something like `specify: %d'.  Note that this may not  work  for  some
              commands.

       avoid-completer
              This  is  used  by  the  _all_matches  completer to decide if the string consisting of all matches
              should be added to the list  currently  being  generated.   Its  value  is  a  list  of  names  of
              completers.   If  any  of  these  is  the name of the completer that generated the matches in this
              completion, the string will not be added.

              The default value for this style is `_expand _old_list _correct _approximate',  i.e.  it  contains
              the completers for which a string with all matches will almost never be wanted.

       cache-path
              This  style  defines  the path where any cache files containing dumped completion data are stored.
              It defaults to `$ZDOTDIR/.zcompcache', or `$HOME/.zcompcache' if $ZDOTDIR  is  not  defined.   The
              completion cache will not be used unless the use-cache style is set.

       cache-policy
              This  style  defines the function that will be used to determine whether a cache needs rebuilding.
              See the section on the _cache_invalid function below.

       call-command
              This style is used in the function for commands such as make and ant  where  calling  the  command
              directly  to  generate  matches suffers problems such as being slow or, as in the case of make can
              potentially cause actions in the makefile to be executed. If it is set to `true'  the  command  is
              called to generate matches. The default value of this style is `false'.

       command
              In  many  places,  completion  functions  need  to  call external commands to generate the list of
              completions.  This style can be used to override the command that is called in  some  such  cases.
              The elements of the value are joined with spaces to form a command line to execute.  The value can
              also  start  with a hyphen, in which case the usual command will be added to the end; this is most
              useful for putting `builtin' or `command' in front to make  sure  the  appropriate  version  of  a
              command is called, for example to avoid calling a shell function with the same name as an external
              command.

              As  an  example, the completion function for process IDs uses this style with the processes tag to
              generate the IDs to complete and the list of  processes  to  display  (if  the  verbose  style  is
              `true').   The  list  produced  by the command should look like the output of the ps command.  The
              first line is not displayed, but is searched for the string `PID' (or `pid') to find the  position
              of  the process IDs in the following lines.  If the line does not contain `PID', the first numbers
              in each of the other lines are taken as the process IDs to complete.

              Note that the completion function generally has to call the specified command for each attempt  to
              generate  the  completion  list.   Hence care should be taken to specify only commands that take a
              short time to run, and in particular to avoid any that may never terminate.

       command-path
              This is a list of directories to search for commands to complete.  The default for this  style  is
              the value of the special parameter path.

       commands
              This  is  used  by  the  function  completing  sub-commands  for the system initialisation scripts
              (residing in /etc/init.d or somewhere not too far away from that).  Its values  give  the  default
              commands  to complete for those commands for which the completion function isn't able to find them
              out automatically.  The default for this style are the two strings `start' and `stop'.

       complete
              This is used by the _expand_alias function when invoked as a bindable command.  If set  to  `true'
              and  the  word  on  the  command  line  is  not the name of an alias, matching alias names will be
              completed.

       complete-options
              This is used by the completer for cd, chdir and  pushd.   For  these  commands  a  -  is  used  to
              introduce  a  directory  stack  entry  and  completion of these is far more common than completing
              options.  Hence unless the value of this style is `true' options will not be completed, even after
              an initial -.  If it is `true', options will be completed after an initial -  unless  there  is  a
              preceding -- on the command line.

       completer
              The  strings given as the value of this style provide the names of the completer functions to use.
              The available completer functions are described in the section `Control Functions' below.

              Each  string  may  be  either  the  name  of  a  completer  function  or  a  string  of  the  form
              `function:name'.   In  the  first case the completer field of the context will contain the name of
              the completer without the leading underscore and with all other underscores replaced  by  hyphens.
              In the second case the function is the name of the completer to call, but the context will contain
              the  user-defined  name  in the completer field of the context.  If the name starts with a hyphen,
              the string for the context will be build from the name of the completer function as in  the  first
              case with the name appended to it.  For example:

                     zstyle ':completion:*' completer _complete _complete:-foo

              Here,  completion  will  call  the _complete completer twice, once using `complete' and once using
              `complete-foo' in the completer field of the context.  Normally, using  the  same  completer  more
              than once only makes sense when used with the `functions:name' form, because otherwise the context
              name  will  be  the  same  in all calls to the completer; possible exceptions to this rule are the
              _ignored and _prefix completers.

              The default value for this style is `_complete _ignored': only  completion  will  be  done,  first
              using the ignored-patterns style and the $fignore array and then without ignoring matches.

       condition
              This  style  is  used  by the _list completer function to decide if insertion of matches should be
              delayed unconditionally. The default is `true'.

       delimiters
              This style is used when adding a delimiter for use with history modifiers or glob qualifiers  that
              have  delimited arguments.  It is an array of preferred delimiters to add.  Non-special characters
              are preferred as the completion system may otherwise become confused.  The default list is  :,  +,
              /, -, %.  The list may be empty to force a delimiter to be typed.

       disabled
              If  this  is  set  to  `true', the _expand_alias completer and bindable command will try to expand
              disabled aliases, too.  The default is `false'.

       domains
              A list of names of network domains for completion.  If this is not set, domain names will be taken
              from the file /etc/resolv.conf.

       environ
              The environ style is used when completing for `sudo'.  It  is  set  to  an  array  of  `VAR=value'
              assignments to be exported into the local environment before the completion for the target command
              is invoked.
              zstyle ':completion:*:sudo::' environ \
                PATH="/sbin:/usr/sbin:$PATH" HOME="/root"

       expand This style is used when completing strings consisting of multiple parts, such as path names.

              If  one  of  its  values  is  the  string `prefix', the partially typed word from the line will be
              expanded as far as possible even if trailing parts cannot be completed.

              If one of its values is the string  `suffix',  matching  names  for  components  after  the  first
              ambiguous one will also be added.  This means that the resulting string is the longest unambiguous
              string possible.  However, menu completion can be used to cycle through all matches.

       fake   This  style  may  be  set  for  any completion context.  It specifies additional strings that will
              always be completed in that context.  The form of each string is  `value:description';  the  colon
              and  description  may be omitted, but any literal colons in value must be quoted with a backslash.
              Any description provided is shown alongside the value in completion listings.

              It is important to use a sufficiently restrictive context when specifying fake strings.  Note that
              the styles fake-files and fake-parameters provide additional features  when  completing  files  or
              parameters.

       fake-always
              This  works identically to the fake style except that the ignored-patterns style is not applied to
              it.  This makes it possible to override a  set  of  matches  completely  by  setting  the  ignored
              patterns to `*'.

              The  following  shows a way of supplementing any tag with arbitrary data, but having it behave for
              display purposes like a separate tag.  In this example we use the features of the tag-order  style
              to  divide  the  named-directories  tag  into  two  when  performing  completion with the standard
              completer complete for arguments of cd.  The tag named-directories-normal behaves as  normal,  but
              the tag named-directories-mine contains a fixed set of directories.  This has the effect of adding
              the match group `extra directories' with the given completions.

                     zstyle ':completion::complete:cd:*' tag-order \
                       'named-directories:-mine:extra\ directories
                       named-directories:-normal:named\ directories *'
                     zstyle ':completion::complete:cd:*:named-directories-mine' \
                       fake-always mydir1 mydir2
                     zstyle ':completion::complete:cd:*:named-directories-mine' \
                       ignored-patterns '*'

       fake-files
              This  style is used when completing files and looked up without a tag.  Its values are of the form
              `dir:names...'.  This will add the names (strings separated by spaces) as  possible  matches  when
              completing  in  the  directory dir, even if no such files really exist.  The dir may be a pattern;
              pattern characters or colons in dir should be quoted with a backslash to be treated literally.

              This can be useful on systems that support special file systems whose top-level pathnames can  not
              be  listed  or  generated  with glob patterns (but see accept-exact-dirs for a more general way of
              dealing with this problem).  It can also be used for directories for which one does not have  read
              permission.

              The  pattern  form  can  be used to add a certain `magic' entry to all directories on a particular
              file system.

       fake-parameters
              This is used by the completion function for parameter names.  Its values are names  of  parameters
              that  might not yet be set but should be completed nonetheless.  Each name may also be followed by
              a colon and a string specifying the type of the parameter (like `scalar', `array'  or  `integer').
              If  the  type is given, the name will only be completed if parameters of that type are required in
              the particular context.  Names for which no type is specified will always be completed.

       file-list
              This style controls whether files completed using the standard builtin mechanism are to be  listed
              with a long list similar to ls -l.  Note that this feature uses the shell module zsh/stat for file
              information;  this  loads  the  builtin  stat which will replace any external stat executable.  To
              avoid this the following code can be included in an initialization file:

                     zmodload -i zsh/stat
                     disable stat

              The style may either be set to a `true' value (or `all'), or one of the values `insert' or `list',
              indicating that files are to be listed in long format in all circumstances, or when attempting  to
              insert a file name, or when listing file names without attempting to insert one.

              More generally, the value may be an array of any of the above values, optionally followed by =num.
              If  num  is  present  it  gives the maximum number of matches for which long listing style will be
              used.  For example,

                     zstyle ':completion:*' file-list list=20 insert=10

              specifies that long format will be used when listing up to 20 files or inserting a file with up to
              10 matches (assuming a listing is to be shown at all, for example  on  an  ambiguous  completion),
              else short format will be used.

                     zstyle -e ':completion:*' file-list \
                            '(( ${+NUMERIC} )) && reply=(true)'

              specifies  that  long  format  will  be  used  any time a numeric argument is supplied, else short
              format.

       file-patterns
              This is used by the standard function for completing filenames, _files.  If the style is unset  up
              to  three  tags are offered, `globbed-files',`directories' and `all-files', depending on the types
              of files  expected by the caller of _files.  The first two (`globbed-files' and `directories') are
              normally offered together to make it easier to complete files in sub-directories.

              The file-patterns style provides alternatives to the default tags, which are not used.  Its  value
              consists  of  elements  of  the  form  `pattern:tag';  each  string may contain any number of such
              specifications separated by spaces.

              The pattern is a pattern that is to be used to generate filenames.  Any occurrence of the sequence
              `%p' is replaced by any pattern(s) passed by the function calling _files.  Colons in  the  pattern
              must  be  preceded  by a backslash to make them distinguishable from the colon before the tag.  If
              more than one pattern is needed, the patterns can be given inside braces, separated by commas.

              The tags of all strings in the value will be offered by _files and  used  when  looking  up  other
              styles.  Any tags in the same word will be offered at the same time and before later words.  If no
              `:tag' is given the `files' tag will be used.

              The tag may also be followed by an optional second colon and a description, which will be used for
              the  `%d'  in  the  value  of the format style (if that is set) instead of the default description
              supplied by the completion function.  If the description given here contains itself a  `%d',  that
              is replaced with the description supplied by the completion function.

              For  example,  to make the rm command first complete only names of object files and then the names
              of all files if there is no matching object file:

                     zstyle ':completion:*:*:rm:*:*' file-patterns \
                         '*.o:object-files' '%p:all-files'

              To alter the default  behaviour  of  file  completion  --  offer  files  matching  a  pattern  and
              directories  on  the  first  attempt,  then all files -- to offer only matching files on the first
              attempt, then directories, and finally all files:

                     zstyle ':completion:*' file-patterns \
                         '%p:globbed-files' '*(-/):directories' '*:all-files'

              This works even where there is no special pattern: _files matches all files using the pattern  `*'
              at the first step and stops when it sees this pattern.  Note also it will never try a pattern more
              than once for a single completion attempt.

              During  the  execution  of  completion  functions,  the  EXTENDED_GLOB option is in effect, so the
              characters `#', `~' and `^' have special meanings in the patterns.

       file-sort
              The standard filename completion function uses this style without a  tag  to  determine  in  which
              order  the names should be listed; menu completion will cycle through them in the same order.  The
              possible values are: `size' to sort by the size of the file; `links' to  sort  by  the  number  of
              links  to  the  file;  `modification' (or `time' or `date') to sort by the last modification time;
              `access' to sort by the last access time; and `inode' (or `change') to  sort  by  the  last  inode
              change  time.   If  the  style  is  set  to  any  other  value,  or is unset, files will be sorted
              alphabetically by name.  If the value contains the  string  `reverse',  sorting  is  done  in  the
              opposite  order.   If  the  value contains the string `follow', timestamps are associated with the
              targets of symbolic links; the default is to use the timestamps of the links themselves.

       file-split-chars
              A set of characters that will cause all file completions for the given context to be split at  the
              point where any of the characters occurs.  A typical use is to set the style to :; then everything
              up  to and including the last : in the string so far is ignored when completing files.  As this is
              quite heavy-handed, it is usually preferable to update completion  functions  for  contexts  where
              this behaviour is useful.

       filter The  ldap plugin of email address completion (see _email_addresses) uses this style to specify the
              attributes to match against when filtering entries.  So for example, if the style is set to  `sn',
              matching  is done against surnames.  Standard LDAP filtering is used so normal completion matching
              is bypassed.  If this style is not set, the LDAP plugin is skipped.  You may also need to set  the
              command style to specify how to connect to your LDAP server.

       force-list
              This  forces  a  list of completions to be shown at any point where listing is done, even in cases
              where the list would usually be suppressed.  For example, normally the list is only shown if there
              are at least two different matches.  By setting this style to `always', the list  will  always  be
              shown, even if there is only a single match that will immediately be accepted.  The style may also
              be  set to a number.  In this case the list will be shown if there are at least that many matches,
              even if they would all insert the same string.

              This style is tested for the default tag as well as for each tag valid for the current completion.
              Hence the listing can be forced only for certain types of match.

       format If this is set for the descriptions tag, its value is used as a string to display above matches in
              completion lists.  The sequence `%d' in this string will be replaced with a short  description  of
              what these matches are.  This string may also contain the output attribute sequences understood by
              compadd -X (see zshcompwid(1)).

              The  style  is  tested  with each tag valid for the current completion before it is tested for the
              descriptions tag.  Hence different format strings can be defined for different types of match.

              Note also that some completer functions define additional `%'-sequences.  These are described  for
              the completer functions that make use of them.

              Some  completion  functions  display messages that may be customised by setting this style for the
              messages tag.  Here, the `%d' is replaced with a message given by the completion function.

              Finally, the format string is looked up with the warnings tag, for use when no  matches  could  be
              generated  at  all.   In this case the `%d' is replaced with the descriptions for the matches that
              were expected separated by spaces.  The sequence `%D'  is  replaced  with  the  same  descriptions
              separated by newlines.

              It  is possible to use printf-style field width specifiers with `%d' and similar escape sequences.
              This is handled by the zformat builtin command from the zsh/zutil module, see zshmodules(1).

       glob   This is used by the _expand completer.  If it is set to `true' (the  default),  globbing  will  be
              attempted  on  the words resulting from a previous substitution (see the substitute style) or else
              the original string from the line.

       global If this is set to `true' (the default), the _expand_alias completer and bindable command will  try
              to expand global aliases.

       group-name
              The  completion system can group different types of matches, which appear in separate lists.  This
              style can be used to give the names of groups  for  particular  tags.   For  example,  in  command
              position the completion system generates names of builtin and external commands, names of aliases,
              shell  functions  and parameters and reserved words as possible completions.  To have the external
              commands and shell functions listed separately:

                     zstyle ':completion:*:*:-command-:*:commands' \
                            group-name commands
                     zstyle ':completion:*:*:-command-:*:functions' \
                            group-name functions

              As a consequence, any match with the same tag will be displayed in the same group.

              If the name given is the empty string the name of the tag for the matches will be used as the name
              of the group.  So, to have all different types of matches displayed separately, one can just set:

                     zstyle ':completion:*' group-name ''

              All matches for which no group name is defined will be put in a group named -default-.

       group-order
              This style is additional to the group-name style to specify the order for display  of  the  groups
              defined  by that style (compare tag-order, which determines which completions appear at all).  The
              groups named are shown in the given order; any other groups are shown in the order defined by  the
              completion function.

              For  example,  to  have names of builtin commands, shell functions and external commands appear in
              that order when completing in command position:

                     zstyle ':completion:*:*:-command-:*:*' group-order \
                            builtins functions commands

       groups A list of names of UNIX groups.  If this is not set, group names are taken from the YP database or
              the file `/etc/group'.

       hidden If this is set to `true', matches  for  the  given  context  will  not  be  listed,  although  any
              description  for  the matches set with the format style will be shown.  If it is set to `all', not
              even the description will be displayed.

              Note that the matches will still be completed; they are just not shown  in  the  list.   To  avoid
              having  matches  considered as possible completions at all, the tag-order style can be modified as
              described below.

       hosts  A list of names of hosts that should be completed.  If this is not set, hostnames are  taken  from
              the file `/etc/hosts'.

       hosts-ports
              This  style  is  used by commands that need or accept hostnames and network ports.  The strings in
              the value should be of the form `host:port'.  Valid  ports  are  determined  by  the  presence  of
              hostnames; multiple ports for the same host may appear.

       ignore-line
              This is tested for each tag valid for the current completion.  If it is set to `true', none of the
              words  that  are  already on the line will be considered as possible completions.  If it is set to
              `current', the word the cursor is on will not be considered as a possible completion.   The  value
              `current-shown'  is  similar but only applies if the list of completions is currently shown on the
              screen.  Finally, if the style is set to `other', all words on the line except for the current one
              will be excluded from the possible completions.

              The values `current' and `current-shown' are a bit like the opposite of  the  accept-exact  style:
              only strings with missing characters will be completed.

              Note  that  you almost certainly don't want to set this to `true' or `other' for a general context
              such as `:completion:*'.  This is because it would disallow completion of,  for  example,  options
              multiple times even if the command in question accepts the option more than once.

       ignore-parents
              The  style  is  tested  without  a  tag by the function completing pathnames in order to determine
              whether to ignore the names of directories already mentioned in the current word, or the  name  of
              the current working directory.  The value must include one or both of the following strings:

              parent The  name  of  any  directory  whose  path  is already contained in the word on the line is
                     ignored.  For example, when completing  after  foo/../,  the  directory  foo  will  not  be
                     considered a valid completion.

              pwd    The  name  of  the  current  working  directory  will not be completed; hence, for example,
                     completion after ../ will not use the name of the current directory.

              In addition, the value may include one or both of:

              ..     Ignore the specified directories only when the word on  the  line  contains  the  substring
                     `../'.

              directory
                     Ignore  the  specified  directories  only when names of directories are completed, not when
                     completing names of files.

              Excluded values act in a similar fashion to values of the ignored-patterns style, so they  can  be
              restored to consideration by the _ignored completer.

       extra-verbose
              If  set,  the  completion listing is more verbose at the cost of a probable decrease in completion
              speed.  Completion performance will suffer if this style is set to `true'.

       ignored-patterns
              A list of patterns; any trial completion matching one  of  the  patterns  will  be  excluded  from
              consideration.  The _ignored completer can appear in the list of completers to restore the ignored
              matches.  This is a more configurable version of the shell parameter $fignore.

              Note  that  the  EXTENDED_GLOB  option is set during the execution of completion functions, so the
              characters `#', `~' and `^' have special meanings in the patterns.

       insert This style is used by the _all_matches completer to decide whether  to  insert  the  list  of  all
              matches unconditionally instead of adding the list as another match.

       insert-ids
              When  completing process IDs, for example as arguments to the kill and wait builtins the name of a
              command may be converted to the appropriate process ID.  A problem arises when  the  process  name
              typed  is  not unique.  By default (or if this style is set explicitly to `menu') the name will be
              converted immediately to a set of possible IDs, and menu  completion  will  be  started  to  cycle
              through them.

              If the value of the style is `single', the shell will wait until the user has typed enough to make
              the  command  unique  before  converting  the  name  to  an  ID;  attempts  at  completion will be
              unsuccessful until that point.  If the value is any other string, menu completion will be  started
              when the string typed by the user is longer than the common prefix to the corresponding IDs.

       insert-tab
              If  this  is  set  to `true', the completion system will insert a TAB character (assuming that was
              used to start completion) instead of performing completion when there is no non-blank character to
              the left of the cursor.  If it is set to `false', completion will be done even there.

              The value may also contain the substrings `pending' or `pending=val'.  In  this  case,  the  typed
              character will be inserted instead of starting completion when there is unprocessed input pending.
              If  a  val  is  given,  completion  will not be done if there are at least that many characters of
              unprocessed input.  This is often useful when pasting characters into a terminal.   Note  however,
              that  it relies on the $PENDING special parameter from the zsh/zle module being set properly which
              is not guaranteed on all platforms.

              The default value of this style is `true' except for completion within vared builtin command where
              it is `false'.

       insert-unambiguous
              This is used by the _match and _approximate completers.  These completers are often used with menu
              completion since the word typed may bear little resemblance to the final completion.  However,  if
              this  style  is  `true',  the  completer  will  start  menu  completion  only  if it could find no
              unambiguous initial string at least as long as the original string typed by the user.

              In the case of the _approximate completer, the completer field in the context  will  already  have
              been  set  to  one  of correct-num or approximate-num, where num is the number of errors that were
              accepted.

              In the case of the _match completer, the style may also be set to the string `pattern'.  Then  the
              pattern on the line is left unchanged if it does not match unambiguously.

       gain-privileges
              If  set to true, this style enables the use of commands like sudo or doas to gain extra privileges
              when retrieving information for completion. This is only done when a command such as sudo  appears
              on  the command-line. To force the use of, e.g. sudo or to override any prefix that might be added
              due to gain-privileges, the command style can be used with a value that begins with a hyphen.

       keep-prefix
              This style is used by the _expand completer.  If it is `true', the completer will try  to  keep  a
              prefix  containing a tilde or parameter expansion.  Hence, for example, the string `~/f*' would be
              expanded to `~/foo' instead of `/home/user/foo'.  If the style is set to `changed' (the  default),
              the  prefix will only be left unchanged if there were other changes between the expanded words and
              the original word from the command line.  Any  other  value  forces  the  prefix  to  be  expanded
              unconditionally.

              The  behaviour  of  _expand when this style is `true' is to cause _expand to give up when a single
              expansion with the restored prefix is the same as the original; hence any remaining completers may
              be called.

       last-prompt
              This is a more flexible form of the ALWAYS_LAST_PROMPT option.  If it is  `true',  the  completion
              system  will  try  to return the cursor to the previous command line after displaying a completion
              list.  It is tested for all tags valid for the current completion,  then  the  default  tag.   The
              cursor  will  be  moved  back to the previous line if this style is `true' for all types of match.
              Note that unlike the ALWAYS_LAST_PROMPT option this is independent of the numeric argument.

       known-hosts-files
              This style should contain a list of files to search for host names and (if  the  use-ip  style  is
              set)  IP addresses in a format compatible with ssh known_hosts files.  If it is not set, the files
              /etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts are used.

       list   This style is used by the _history_complete_word bindable command.  If it is set to `true' it  has
              no effect.  If it is set to `false' matches will not be listed.  This overrides the setting of the
              options  controlling  listing  behaviour, in particular AUTO_LIST.  The context always starts with
              `:completion:history-words'.

       list-colors
              If the zsh/complist module is loaded, this style can be used to set  color  specifications.   This
              mechanism  replaces  the use of the ZLS_COLORS and ZLS_COLOURS parameters described in the section
              `The zsh/complist Module' in zshmodules(1), but the syntax is the same.

              If this style is set for the default tag, the strings in the value  are  taken  as  specifications
              that are to be used everywhere.  If it is set for other tags, the specifications are used only for
              matches of the type described by the tag.  For this to work best, the group-name style must be set
              to an empty string.

              In  addition to setting styles for specific tags, it is also possible to use group names specified
              explicitly by the group-name tag together with the `(group)' syntax allowed by the ZLS_COLORS  and
              ZLS_COLOURS parameters and simply using the default tag.

              It  is  possible  to  use  any  color  specifications already set up for the GNU version of the ls
              command:

                     zstyle ':completion:*:default' list-colors \
                            ${(s.:.)LS_COLORS}

              The default colors are the same as for the GNU ls command and can be obtained by setting the style
              to an empty string (i.e. '').

       list-dirs-first
              This is used by file completion.  If set, directories to be completed are listed  separately  from
              and  before  completion  for  other  files,  regardless  of  tag  ordering.   In addition, the tag
              other-files is used in place of all-files for the remaining files, to indicate that no directories
              are presented with that tag.

       list-grouped
              If this style is `true' (the default), the completion system will try to make  certain  completion
              listings  more  compact by grouping matches.  For example, options for commands that have the same
              description (shown when the verbose style is set  to  `true')  will  appear  as  a  single  entry.
              However, menu selection can be used to cycle through all the matches.

       list-packed
              This is tested for each tag valid in the current context as well as the default tag.  If it is set
              to `true', the corresponding matches appear in listings as if the LIST_PACKED option were set.  If
              it is set to `false', they are listed normally.

       list-prompt
              If  this  style  is  set for the default tag, completion lists that don't fit on the screen can be
              scrolled (see the description of the zsh/complist module in zshmodules(1)).  The value, if not the
              empty string, will be displayed after every screenful and the shell will prompt for a  key  press;
              if the style is set to the empty string, a default prompt will be used.

              The  value may contain the escape sequences: `%l' or `%L', which will be replaced by the number of
              the last line displayed and the total number of lines; `%m' or `%M', the number of the  last match
              shown and the total number of matches; and `%p' and `%P', `Top' when at the beginning of the list,
              `Bottom' when at the end and the position shown as a percentage of the total length otherwise.  In
              each case the form with the uppercase letter will be replaced by a string of fixed  width,  padded
              to  the   right with spaces, while the lowercase form will be replaced by a variable width string.
              As in other prompt strings, the escape sequences `%S', `%s', `%B', `%b', `%U', `%u'  for  entering
              and  leaving  the  display  modes  standout,  bold  and  underline, and `%F', `%f', `%K', `%k' for
              changing the foreground background colour, are also  available,  as  is  the  form  `%{...%}'  for
              enclosing  escape  sequences  which  display  with  zero (or, with a numeric argument, some other)
              width.

              After deleting this prompt the variable LISTPROMPT should be unset for the removal to take effect.

       list-rows-first
              This style is tested in the same way as the list-packed style and determines whether  matches  are
              to be listed in a rows-first fashion as if the LIST_ROWS_FIRST option were set.

       list-suffixes
              This  style  is used by the function that completes filenames.  If it is `true', and completion is
              attempted on a string containing multiple  partially  typed  pathname  components,  all  ambiguous
              components will be shown.  Otherwise, completion stops at the first ambiguous component.

       list-separator
              The  value  of  this style is used in completion listing to separate the string to complete from a
              description when possible (e.g. when completing options).  It defaults to `--' (two hyphens).

       local  This is for use with functions that complete URLs for which the corresponding files are  available
              directly from the file system.  Its value should consist of three strings: a hostname, the path to
              the  default  web  pages  for  the server, and the directory name used by a user placing web pages
              within their home area.

              For example:

                     zstyle ':completion:*' local toast \
                         /var/http/public/toast public_html

              Completion   after   `http://toast/stuff/'   will   look    for    files    in    the    directory
              /var/http/public/toast/stuff,   while completion after `http://toast/~yousir/' will look for files
              in the directory ~yousir/public_html.

       mail-directory
              If set, zsh will assume that mailbox files can be found in the directory specified.   It  defaults
              to `~/Mail'.

       match-original
              This  is  used by the _match completer.  If it is set to only, _match will try to generate matches
              without inserting a `*' at the cursor position.  If set to any  other  non-empty  value,  it  will
              first try to generate matches without inserting the `*' and if that yields no matches, it will try
              again  with  the  `*'  inserted.  If it is unset or set to the empty string, matching will only be
              performed with the `*' inserted.

       matcher
              This style is tested separately for each tag valid in the current context.  Its  value  is  placed
              before  any  match specifications given by the matcher-list style so can override them via the use
              of an x: specification.  The value should be in the form  described  in  the  section  `Completion
              Matching  Control'  in  zshcompwid(1).  For examples of this, see the description of the tag-order
              style.

              For notes comparing the use of this and the matcher-list style, see under the description  of  the
              tag-order style.

       matcher-list
              This  style  can be set to a list of match specifications that are to be applied everywhere. Match
              specifications are described in the section `Completion Matching Control' in  zshcompwid(1).   The
              completion  system  will  try them one after another for each completer selected.  For example, to
              try first simple completion and, if that generates no matches, case-insensitive completion:

                     zstyle ':completion:*' matcher-list '' 'm:{a-zA-Z}={A-Za-z}'

              By default each specification replaces the previous one; however, if a specification  is  prefixed
              with  +,  it  is  added to the existing list.  Hence it is possible to create increasingly general
              specifications without repetition:

                     zstyle ':completion:*' matcher-list \
                            '' '+m:{a-z}={A-Z}' '+m:{A-Z}={a-z}'

              It is possible to create match specifications valid for particular completers by using  the  third
              field  of  the  context.   This  applies only to completers that override the global matcher-list,
              which as of this writing includes only _prefix and _ignored.  For example, to use  the  completers
              _complete and _prefix but allow case-insensitive completion only with _complete:

                     zstyle ':completion:*' completer _complete _prefix
                     zstyle ':completion:*:complete:*:*:*' matcher-list \
                            '' 'm:{a-zA-Z}={A-Za-z}'

              User-defined  names,  as explained for the completer style, are available.  This makes it possible
              to try the same completer more than once with  different  match  specifications  each  time.   For
              example,  to  try  normal  completion  without  a match specification, then normal completion with
              case-insensitive matching, then correction, and finally partial-word completion:

                     zstyle ':completion:*' completer \
                         _complete _correct _complete:foo
                     zstyle ':completion:*:complete:*:*:*' matcher-list \
                         '' 'm:{a-zA-Z}={A-Za-z}'
                     zstyle ':completion:*:foo:*:*:*' matcher-list \
                         'm:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*'

              If the style is unset in any context no match specification  is  applied.   Note  also  that  some
              completers  such  as  _correct and _approximate do not use the match specifications at all, though
              these completers will only ever be called once even if the matcher-list  contains  more  than  one
              element.

              Where multiple specifications are useful, note that the entire completion is done for each element
              of  matcher-list, which can quickly reduce the shell's performance.  As a rough rule of thumb, one
              to three  strings  will  give  acceptable  performance.   On  the  other  hand,  putting  multiple
              space-separated values into the same string does not have an appreciable impact on performance.

              If  there  is  no  current  matcher  or it is empty, and the option NO_CASE_GLOB is in effect, the
              matching for files is performed  case-insensitively  in  any  case.   However,  any  matcher  must
              explicitly specify case-insensitive matching if that is required.

              For  notes  comparing  the  use  of  this  and the matcher style, see under the description of the
              tag-order style.

       max-errors
              This is used by the _approximate and _correct completer functions to determine the maximum  number
              of  errors  to allow.  The completer will try to generate completions by first allowing one error,
              then two errors, and so on, until either a match or matches were found or the  maximum  number  of
              errors given by this style has been reached.

              If  the  value  for this style contains the string `numeric', the completer function will take any
              numeric argument as the maximum number of errors allowed. For example, with

                     zstyle ':completion:*:approximate:::' max-errors 2 numeric

              two errors are allowed if no numeric argument is given, but with a numeric argument of six (as  in
              `ESC-6  TAB'),  up  to  six errors are accepted.  Hence with a value of `0 numeric', no correcting
              completion will be attempted unless a numeric argument is given.

              If the value contains the string `not-numeric', the completer will not try to  generate  corrected
              completions when given a numeric argument, so in this case the number given should be greater than
              zero.   For  example,  `2  not-numeric'  specifies that correcting completion with two errors will
              usually be performed, but if a numeric argument  is  given,  correcting  completion  will  not  be
              performed.

              The default value for this style is `2 numeric'.

       max-matches-width
              This  style  is  used to determine the trade off between the width of the display used for matches
              and the width used for their descriptions when the verbose style is in effect.   The  value  gives
              the  number  of  display columns to reserve for the matches.  The default is half the width of the
              screen.

              This has the most impact when several matches have the same description and  so  will  be  grouped
              together.  Increasing the style will allow more matches to be grouped together; decreasing it will
              allow more of the description to be visible.

       menu   If  this  is  `true'  in  the  context  of any of the tags defined for the current completion menu
              completion will be used.  The value for a specific tag will take  precedence  over  that  for  the
              `default' tag.

              If  none  of  the  values found in this way is `true' but at least one is set to `auto', the shell
              behaves as if the AUTO_MENU option is set.

              If one of the values is explicitly set to `false', menu completion will be explicitly turned  off,
              overriding the MENU_COMPLETE option and other settings.

              In  the form `yes=num', where `yes' may be any of the `true' values (`yes', `true', `on' and `1'),
              menu completion will be turned on if there are at least num matches.  In the form `yes=long', menu
              completion will be turned on if the list does not fit on the screen.  This does not activate  menu
              completion  if the widget normally only lists completions, but menu completion can be activated in
              that case with the value `yes=long-list' (Typically, the value `select=long-list' described  later
              is more useful as it provides control over scrolling.)

              Similarly,  with  any  of  the `false' values (as in `no=10'), menu completion will not be used if
              there are num or more matches.

              The value of this widget also controls menu selection, as implemented by the zsh/complist  module.
              The following values may appear either alongside or instead of the values above.

              If the value contains the string `select', menu selection will be started unconditionally.

              In  the  form `select=num', menu selection will only be started if there are at least num matches.
              If the values for more than one tag provide a number, the smallest number is taken.

              Menu selection can be turned off explicitly by defining a value containing the string`no-select'.

              It is also possible to start menu selection only if the list of matches does not fit on the screen
              by using the value `select=long'.  To start  menu  selection  even  if  the  current  widget  only
              performs listing, use the value `select=long-list'.

              To  turn  on  menu  completion or menu selection when there are a certain number of matches or the
              list of matches does not fit on the screen, both of `yes=' and `select=' may be given twice,  once
              with a number and once with `long' or `long-list'.

              Finally,  it  is possible to activate two special modes of menu selection.  The word `interactive'
              in the value causes interactive mode to be entered immediately when menu selection is started; see
              the description of the zsh/complist module in zshmodules(1) for a description of interactive mode.
              Including the string `search' does the same for  incremental  search  mode.   To  select  backward
              incremental search, include the string `search-backward'.

       muttrc If set, gives the location of the mutt configuration file.  It defaults to `~/.muttrc'.

       numbers
              This  is  used with the jobs tag.  If it is `true', the shell will complete job numbers instead of
              the shortest unambiguous prefix of the job command text.  If the value is a  number,  job  numbers
              will  only  be  used  if  that  many  words  from  the  job  descriptions  are required to resolve
              ambiguities.  For example, if the value is `1', strings will only be used if all  jobs  differ  in
              the first word on their command lines.

       old-list
              This  is  used  by  the _oldlist completer.  If it is set to `always', then standard widgets which
              perform listing will retain the current list of matches, however they were generated; this can  be
              turned off explicitly with the value `never', giving the behaviour without the _oldlist completer.
              If  the  style is unset, or any other value, then the existing list of completions is displayed if
              it is not already; otherwise, the standard completion list  is  generated;  this  is  the  default
              behaviour  of  _oldlist.  However, if there is an old list and this style contains the name of the
              completer function that generated the list, then the  old  list  will  be  used  even  if  it  was
              generated by a widget which does not do listing.

              For  example,  suppose  you  type  ^Xc  to use the _correct_word widget, which generates a list of
              corrections for the word under the cursor.  Usually, typing ^D would generate a standard  list  of
              completions  for the word on the command line, and show that.  With _oldlist, it will instead show
              the list of corrections already generated.

              As another example consider the _match completer: with the insert-unambiguous style set to  `true'
              it  inserts  only  a common prefix string, if there is any.  However, this may remove parts of the
              original pattern, so that further completion could produce more matches than on the first attempt.
              By using the _oldlist completer and setting this style to _match, the list of matches generated on
              the first attempt will be used again.

       old-matches
              This is used by the _all_matches completer to decide if an old list of matches should be  used  if
              one  exists.   This is selected by one of the `true' values or by the string `only'.  If the value
              is `only', _all_matches will only use an old list and won't have any effect on the list of matches
              currently being generated.

              If this style is set it is generally unwise to call the  _all_matches  completer  unconditionally.
              One  possible use is for either this style or the completer style to be defined with the -e option
              to zstyle to make the style conditional.

       old-menu
              This is used by the _oldlist completer.  It controls how menu completion behaves when a completion
              has already been inserted and the user types a standard completion key such as TAB.   The  default
              behaviour  of  _oldlist  is  that  menu  completion  always  continues  with  the existing list of
              completions.  If this style is set to `false', however, a new completion is  started  if  the  old
              list  was  generated by a different completion command; this is the behaviour without the _oldlist
              completer.

              For example, suppose you type ^Xc to generate a  list  of  corrections,  and  menu  completion  is
              started  in one of the usual ways.  Usually, or with this style set to `false', typing TAB at this
              point would start trying to complete the line as  it  now  appears.   With  _oldlist,  it  instead
              continues to cycle through the list of corrections.

       original
              This  is  used by the _approximate and _correct completers to decide if the original string should
              be added as a possible completion.  Normally, this is done only if there are at least two possible
              corrections, but if this style is set to `true', it is always added.  Note that the style will  be
              examined with the completer field in the context name set to correct-num or approximate-num, where
              num is the number of errors that were accepted.

       packageset
              This  style  is  used  when  completing  arguments  of  the Debian `dpkg' program.  It contains an
              override for the default package set for a given context.  For example,

                     zstyle ':completion:*:complete:dpkg:option--status-1:*' \
                                    packageset avail

              causes available packages, rather  than  only  installed  packages,  to  be  completed  for  `dpkg
              --status'.

       path   The  function that completes color names uses this style with the colors tag.  The value should be
              the pathname of a file containing color names in the format of an X11 rgb.txt file.  If the  style
              is  not  set  but  this  file is found in one of various standard locations it will be used as the
              default.

       path-completion
              This is used by filename completion.  By default, filename completion examines all components of a
              path to see if there are completions of that component.  For example, /u/b/z can be  completed  to
              /usr/bin/zsh.   Explicitly  setting  this  style  to  `false'  inhibits  this  behaviour  for path
              components up to the / before the cursor; this overrides the setting of accept-exact-dirs.

              Even with the style set to `false', it is still possible to complete multiple paths by setting the
              option COMPLETE_IN_WORD and moving the cursor back to the  first  component  in  the  path  to  be
              completed.  For example, /u/b/z can be completed to /usr/bin/zsh if the cursor is after the /u.

       pine-directory
              If  set,  specifies  the  directory  containing  PINE  mailbox  files.  There is no default, since
              recursively searching this directory is inconvenient for anyone who doesn't use PINE.

       ports  A list of Internet service names (network ports) to complete.  If this is not set,  service  names
              are taken from the file `/etc/services'.

       prefix-hidden
              This  is  used  for  certain  completions which share a common prefix, for example command options
              beginning with dashes.  If it is `true', the prefix will not be shown in the list of matches.

              The default value for this style is `false'.

       prefix-needed
              This style is also relevant for matches with a common prefix.  If it is set to `true' this  common
              prefix must be typed by the user to generate the matches.

              The style is applicable to the options, signals, jobs, functions, and parameters completion tags.

              For command options, this means that the initial `-', `+', or `--' must be typed explicitly before
              option names will be completed.

              For signals, an initial `-' is required before signal names will be completed.

              For jobs, an initial `%' is required before job names will be completed.

              For  function  and parameter names, an initial `_' or `.' is required before function or parameter
              names starting with those characters will be completed.

              The default value for this style is `false' for function and parameter  completions,  and   `true'
              otherwise.

       preserve-prefix
              This  style is used when completing path names.  Its value should be a pattern matching an initial
              prefix of the word to complete that  should  be  left  unchanged  under  all  circumstances.   For
              example,  on  some Unices an initial `//' (double slash) has a special meaning; setting this style
              to the string `//' will preserve it.  As another example, setting this style to `?:/' under Cygwin
              would allow completion after `a:/...' and so on.

       range  This is used by the _history completer and the _history_complete_word bindable command  to  decide
              which words should be completed.

              If it is a single number, only the last N words from the history will be completed.

              If  it  is  a  range of the form `max:slice', the last slice words will be completed; then if that
              yields no matches, the slice words before those will be tried  and  so  on.   This  process  stops
              either when at least one match has been found, or max words have been tried.

              The default is to complete all words from the history at once.

       recursive-files
              If  this  style  is  set, its value is an array of patterns to be tested against `$PWD/': note the
              trailing slash, which allows directories in the pattern to be delimited unambiguously by including
              slashes on both sides.  If an ordinary file completion fails and the word on the command line does
              not yet have a directory part to its name, the style is retrieved using the same tag  as  for  the
              completion  just  attempted, then the elements tested against $PWD/ in turn.  If one matches, then
              the shell reattempts completion by prepending the word on the command line with each directory  in
              the expansion of **/*(/) in turn.  Typically the elements of the style will be set to restrict the
              number of directories beneath the current one to a manageable number, for example `*/.git/*'.

              For example,

                     zstyle ':completion:*' recursive-files '*/zsh/*'

              If   the   current   directory   is   /home/pws/zsh/Src,   then  zle_trTAB  can  be  completed  to
              Zle/zle_tricky.c.

       regular
              This style is used by the _expand_alias completer and bindable command.  If  set  to  `true'  (the
              default), regular aliases will be expanded but only in command position.  If it is set to `false',
              regular  aliases  will  never  be  expanded.    If  it is set to `always', regular aliases will be
              expanded even if not in command position.

       rehash If this is set when completing external commands, the internal list (hash)  of  commands  will  be
              updated for each search by issuing the rehash command.  There is a speed penalty for this which is
              only likely to be noticeable when directories in the path have slow file access.

       remote-access
              If set to `false', certain commands will be prevented from making Internet connections to retrieve
              remote information.  This includes the completion for the CVS command.

              It  is  not  always  possible  to know if connections are in fact to a remote site, so some may be
              prevented unnecessarily.

       remove-all-dups
              The _history_complete_word bindable command and the _history completer use this to decide  if  all
              duplicate matches should be removed, rather than just consecutive duplicates.

       select-prompt
              If  this  is  set  for the default tag, its value will be displayed during menu selection (see the
              menu style above) when the completion list does not fit on  the  screen  as  a  whole.   The  same
              escapes as for the list-prompt style are understood, except that the numbers refer to the match or
              line the mark is on.  A default prompt is used when the value is the empty string.

       select-scroll
              This style is tested for the default tag and determines how a completion list is scrolled during a
              menu selection (see the menu style above) when the completion list does not fit on the screen as a
              whole.   If  the value is `0' (zero), the list is scrolled by half-screenfuls; if it is a positive
              integer, the list is scrolled by the given number of lines; if it is a negative number,  the  list
              is  scrolled by a screenful minus the absolute value of the given number of lines.  The default is
              to scroll by single lines.

       separate-sections
              This style is used with the manuals tag when completing names of manual pages.  If it  is  `true',
              entries  for different sections are added separately using tag names of the form `manual.X', where
              X is the section number.  When the group-name style  is  also  in  effect,  pages  from  different
              sections  will  appear  separately.   This  style is also used similarly with the words style when
              completing words for the dict command. It allows words from different dictionary databases  to  be
              added separately.  The default for this style is `false'.

       show-ambiguity
              If  the  zsh/complist  module  is  loaded, this style can be used to highlight the first ambiguous
              character in completion lists. The value is either a color indication such as those  supported  by
              the  list-colors  style  or,  with  a  value  of `true', a default of underlining is selected. The
              highlighting is only applied if the completion display strings correspond to the actual matches.

       show-completer
              Tested whenever a new completer is tried.  If it  is  `true',  the  completion  system  outputs  a
              progress  message  in the listing area showing what completer is being tried.  The message will be
              overwritten by any output when completions are found and is removed after completion is finished.

       single-ignored
              This is used by the _ignored completer when there is only one match.  If its value is `show',  the
              single  match  will  be displayed but not inserted.  If the value is `menu', then the single match
              and the original string are both added as matches and menu completion is started, making  it  easy
              to select either of them.

       sort   This allows the standard ordering of matches to be overridden.

              If  its  value  is  `true'  or  `false',  sorting is enabled or disabled.  Additionally the values
              associated with the `-o' option to compadd can also be listed: match,  nosort,  numeric,  reverse.
              If it is not set for the context, the standard behaviour of the calling widget is used.

              The style is tested first against the full context including the tag, and if that fails to produce
              a value against the context without the tag.

              In  many  cases  where  a  calling  widget explicitly selects a particular ordering in lieu of the
              default, a value of `true' is not honoured.  An example of where this  is  not  the  case  is  for
              command  history where the default of sorting matches chronologically may be overridden by setting
              the style to `true'.

              In the _expand completer, if it is set to `true', the expansions generated will always be  sorted.
              If  it  is  set  to  `menu',  then  the expansions are only sorted when they are offered as single
              strings but not in the string containing all possible expansions.

       special-dirs
              Normally, the completion code will not produce the  directory  names  `.'  and  `..'  as  possible
              completions.   If  this  style  is  set  to  `true',  it  will  add  both `.' and `..' as possible
              completions; if it is set to `..', only `..' will be added.

              The following example sets special-dirs to `..' when the current prefix is empty, is a single `.',
              or consists only of a path beginning with `../'.  Otherwise the value is `false'.

                     zstyle -e ':completion:*' special-dirs \
                        '[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)'

       squeeze-slashes
              If set to `true', sequences of slashes in filename paths  (for  example  in  `foo//bar')  will  be
              treated  as  a  single slash.  This is the usual behaviour of UNIX paths.  However, by default the
              file completion function behaves as if there were a `*' between the slashes.

       stop   If set to `true', the _history_complete_word bindable command will stop  once  when  reaching  the
              beginning  or  end  of  the history.  Invoking _history_complete_word will then wrap around to the
              opposite  end  of  the  history.    If   this   style   is   set   to   `false'   (the   default),
              _history_complete_word will loop immediately as in a menu completion.

       strip-comments
              If  set  to  `true',  this  style  causes non-essential comment text to be removed from completion
              matches.  Currently it is only used when completing e-mail addresses where it removes any  display
              name from the addresses, cutting them down to plain user@host form.

       subst-globs-only
              This is used by the _expand completer.  If it is set to `true', the expansion will only be used if
              it  resulted  from  globbing;  hence,  if expansions resulted from the use of the substitute style
              described below, but these were not further changed by globbing, the expansions will be rejected.

              The default for this style is `false'.

       substitute
              This boolean  style  controls  whether  the  _expand  completer  will  first  try  to  expand  all
              substitutions in the string (such as `$(...)' and `${...}').

              The default is `true'.

       suffix This  is  used  by  the  _expand completer if the word starts with a tilde or contains a parameter
              expansion.  If it is set to `true', the word will only be expanded if it doesn't  have  a  suffix,
              i.e.  if  it  is  something  like  `~foo' or `$foo' rather than `~foo/' or `$foo/bar', unless that
              suffix itself contains characters eligible for expansion.  The default for this style is `true'.

       tag-order
              This provides a mechanism for sorting how the tags available in a particular context will be used.

              The values for the style are sets of space-separated lists of tags.  The tags in each  value  will
              be  tried  at the same time; if no match is found, the next value is used.  (See the file-patterns
              style for an exception to this behavior.)

              For example:

                     zstyle ':completion:*:complete:-command-:*:*' tag-order \
                         'commands functions'

              specifies that completion in command position first offers external commands and shell  functions.
              Remaining tags will be tried if no completions are found.

              In addition to tag names, each string in the value may take one of the following forms:

              -      If  any  value  consists of only a hyphen, then only the tags specified in the other values
                     are generated.  Normally all tags not explicitly selected are tried last if  the  specified
                     tags  fail  to  generate  any matches.  This means that a single value consisting only of a
                     single hyphen turns off completion.

              ! tags...
                     A string starting with an exclamation mark specifies names of tags that are not to be used.
                     The effect is the same as if all other possible tags for the context had been listed.

              tag:label ...
                     Here, tag is one of the standard  tags  and  label  is  an  arbitrary  name.   Matches  are
                     generated  as  normal  but  the name label is used in contexts instead of tag.  This is not
                     useful in words starting with !.

                     If the label starts with a hyphen, the tag is prepended to the label to form the name  used
                     for  lookup.   This  can  be used to make the completion system try a certain tag more than
                     once, supplying different style settings for each attempt; see below for an example.

              tag:label:description
                     As before, but description will replace the `%d' in the value of the format  style  instead
                     of  the default description supplied by the completion function.  Spaces in the description
                     must be quoted with a backslash.  A `%d' appearing in  description  is  replaced  with  the
                     description given by the completion function.

              In  any  of  the  forms  above  the  tag  may  be  a  pattern  or  several  patterns  in  the form
              `{pat1,pat2...}'.  In this case all matching tags will be used except for any given explicitly  in
              the same string.

              One  use  of  these features is to try one tag more than once, setting other styles differently on
              each attempt, but still to use all the other tags without having to repeat them all.  For example,
              to make completion of function names in command  position  ignore  all  the  completion  functions
              starting with an underscore the first time completion is tried:

                     zstyle ':completion:*:*:-command-:*:*' tag-order \
                         'functions:-non-comp *' functions
                     zstyle ':completion:*:functions-non-comp' \
                         ignored-patterns '_*'

              On  the  first  attempt,  all  tags  will  be  offered  but  the functions tag will be replaced by
              functions-non-comp.  The ignored-patterns style is set for this tag to exclude functions  starting
              with  an  underscore.   If  there  are no matches, the second value of the tag-order style is used
              which completes functions using the default tag,  this  time  presumably  including  all  function
              names.

              The matches for one tag can be split into different groups.  For example:

                     zstyle ':completion:*' tag-order \
                         'options:-long:long\ options
                          options:-short:short\ options
                          options:-single-letter:single\ letter\ options'
                     zstyle ':completion:*:options-long' \
                          ignored-patterns '[-+](|-|[^-]*)'
                     zstyle ':completion:*:options-short' \
                          ignored-patterns '--*' '[-+]?'
                     zstyle ':completion:*:options-single-letter' \
                          ignored-patterns '???*'

              With  the  group-names style set, options beginning with `--', options beginning with a single `-'
              or `+' but containing multiple characters, and single-letter options will be displayed in separate
              groups with different descriptions.

              Another use of  patterns  is  to  try  multiple  match  specifications  one  after  another.   The
              matcher-list  style offers something similar, but it is tested very early in the completion system
              and hence can't be set for single commands nor for more specific contexts.  Here  is  how  to  try
              normal  completion  without  any  match specification and, if that generates no matches, try again
              with case-insensitive matching, restricting the effect to arguments of the command foo:

                     zstyle ':completion:*:*:foo:*:*' tag-order '*' '*:-case'
                     zstyle ':completion:*-case' matcher 'm:{a-z}={A-Z}'

              First, all the tags offered when completing after foo are tried using the  normal  tag  name.   If
              that  generates  no  matches,  the  second  value of tag-order is used, which tries all tags again
              except that this time each has -case appended to its name for lookup of styles.  Hence  this  time
              the  value  for  the  matcher  style from the second call to zstyle in the example is used to make
              completion case-insensitive.

              It is possible to use the -e option of the zstyle builtin command to specify  conditions  for  the
              use of particular tags.  For example:

                     zstyle -e '*:-command-:*' tag-order '
                         if [[ -n $PREFIX$SUFFIX ]]; then
                           reply=( )
                         else
                           reply=( - )
                         fi'

              Completion  in  command  position  will be attempted only if the string typed so far is not empty.
              This is tested using the PREFIX special parameter; see zshcompwid for a description of  parameters
              which are special inside completion widgets.  Setting reply to an empty array provides the default
              behaviour of trying all tags at once; setting it to an array containing only a hyphen disables the
              use of all tags and hence of all completions.

              If  no  tag-order style has been defined for a context, the strings `(|*-)argument-* (|*-)option-*
              values' and `options' plus all tags offered by the completion function will be used to  provide  a
              sensible  default behavior that causes arguments (whether normal command arguments or arguments of
              options) to be completed before option names for most commands.

       urls   This is used together with the urls tag by functions completing URLs.

              If the value consists of more than one string, or if the only string  does  not  name  a  file  or
              directory, the strings are used as the URLs to complete.

              If  the  value contains only one string which is the name of a normal file the URLs are taken from
              that file (where the URLs may be separated by white space or newlines).

              Finally, if the only string in the value names a directory, the directory hierarchy rooted at this
              directory gives the completions.  The top level directory should be the file access  method,  such
              as  `http',  `ftp',  `bookmark'  and so on.  In many cases the next level of directories will be a
              filename.  The directory hierarchy can descend as deep as necessary.

              For example,

                     zstyle ':completion:*' urls ~/.urls
                     mkdir -p ~/.urls/ftp/ftp.zsh.org/pub

              allows completion of all the components of the URL ftp://ftp.zsh.org/pub after  suitable  commands
              such  as  `netscape'  or  `lynx'.   Note,  however,  that  access  methods and files are completed
              separately, so if the hosts style is set hosts can be completed  without  reference  to  the  urls
              style.

              See   the   description   in   the   function  _urls  itself  for  more  information  (e.g.  `more
              $^fpath/_urls(N)').

       use-cache
              If this is set, the completion caching layer is activated for any completions which  use  it  (via
              the  _store_cache,  _retrieve_cache,  and _cache_invalid functions).  The directory containing the
              cache files can be changed with the cache-path style.

       use-compctl
              If this style is set to a string not equal to false, 0, no, and off, the completion system may use
              any completion specifications defined with the compctl builtin command.  If the  style  is  unset,
              this  is done only if the zsh/compctl module is loaded.  The string may also contain the substring
              `first' to use completions defined with `compctl -T', and  the  substring  `default'  to  use  the
              completion defined with `compctl -D'.

              Note that this is only intended to smooth the transition from compctl to the new completion system
              and may disappear in the future.

              Note  also  that the definitions from compctl will only be used if there is no specific completion
              function for the command in question.  For example, if  there  is  a  function  _foo  to  complete
              arguments to the command foo, compctl will never be invoked for foo.  However, the compctl version
              will be tried if foo only uses default completion.

       use-ip By  default,  the  function _hosts that completes host names strips IP addresses from entries read
              from host databases such as NIS and ssh files.  If this style  is  `true',  the  corresponding  IP
              addresses can be completed as well.  This style is not use in any context where the hosts style is
              set;  note  also  it  must be set before the cache of host names is generated (typically the first
              completion attempt).

       users  This may be set to a list of usernames to be completed.  If it is not set all  usernames  will  be
              completed.   Note  that if it is set only that list of users will be completed; this is because on
              some systems querying all users can take a prohibitive amount of time.

       users-hosts
              The values of this style should be of the form `user@host' or `user:host'. It is used for commands
              that need pairs of user- and hostnames.  These commands will complete usernames  from  this  style
              (only),  and will restrict subsequent hostname completion to hosts paired with that user in one of
              the values of the style.

              It is possible to group values for sets of commands which allow a remote login, such as rlogin and
              ssh, by using the my-accounts tag.  Similarly, values for sets of commands which usually refer  to
              the  accounts of other people, such as talk and finger, can be grouped by using the other-accounts
              tag.  More ambivalent commands may use the accounts tag.

       users-hosts-ports
              Like  users-hosts  but  used  for  commands  like  telnet  and  containing  strings  of  the  form
              `user@host:port'.

       verbose
              If  set, as it is by default, the completion listing is more verbose.  In particular many commands
              show descriptions for options if this style is `true'.

       word   This is used by the _list completer, which prevents the insertion of completions  until  a  second
              completion  attempt  when the line has not changed.  The normal way of finding out if the line has
              changed is to compare its entire contents between the two occasions.  If this style is `true', the
              comparison is instead performed only on the current word.  Hence if  completion  is  performed  on
              another word with the same contents, completion will not be delayed.

CONTROL FUNCTIONS

       The  initialization  script  compinit  redefines  all  the  widgets  which perform completion to call the
       supplied widget function  _main_complete.   This  function  acts  as  a  wrapper  calling  the  so-called
       `completer' functions that generate matches.  If _main_complete is called with arguments, these are taken
       as  the names of completer functions to be called in the order given.  If no arguments are given, the set
       of functions to try is taken from the completer  style.   For  example,  to  use  normal  completion  and
       correction if that doesn't generate any matches:

              zstyle ':completion:*' completer _complete _correct

       after  calling  compinit.  The  default  value for this style is `_complete _ignored', i.e. normally only
       ordinary completion is tried, first with the effect of the ignored-patterns style and  then  without  it.
       The  _main_complete  function  uses  the  return  status  of  the  completer functions to decide if other
       completers should be called.  If the return status is  zero,  no  other  completers  are  tried  and  the
       _main_complete function returns.

       If  the  first argument to _main_complete is a single hyphen, the arguments will not be taken as names of
       completers.  Instead, the second argument gives a name to use in the completer field of the  context  and
       the other arguments give a command name and arguments to call to generate the matches.

       The  following completer functions are contained in the distribution, although users may write their own.
       Note that in contexts the leading underscore is stripped, for example basic completion  is  performed  in
       the context `:completion::complete:...'.

       _all_matches
              This  completer  can  be  used  to add a string consisting of all other matches.  As it influences
              later completers it must appear as the first completer in the list.  The list of  all  matches  is
              affected by the avoid-completer and old-matches styles described above.

              It  may  be  useful  to  use the _generic function described below to bind _all_matches to its own
              keystroke, for example:

                     zle -C all-matches complete-word _generic
                     bindkey '^Xa' all-matches
                     zstyle ':completion:all-matches:*' old-matches only
                     zstyle ':completion:all-matches::::' completer _all_matches

              Note that this does not generate completions by itself:  first use any of  the  standard  ways  of
              generating a list of completions, then use ^Xa to show all matches.  It is possible instead to add
              a  standard  completer  to  the  list  and request that the list of all matches should be directly
              inserted:

                     zstyle ':completion:all-matches::::' completer \
                            _all_matches _complete
                     zstyle ':completion:all-matches:*' insert true

              In this case the old-matches style should not be set.

       _approximate
              This is  similar  to  the  basic  _complete  completer  but  allows  the  completions  to  undergo
              corrections.   The  maximum  number  of  errors  can be specified by the max-errors style; see the
              description of approximate matching in zshexpn(1) for  how  errors  are  counted.   Normally  this
              completer will only be tried after the normal _complete completer:

                     zstyle ':completion:*' completer _complete _approximate

              This  will  give  correcting  completion  if  and  only  if  normal  completion yields no possible
              completions.  When corrected completions  are  found,  the  completer  will  normally  start  menu
              completion allowing you to cycle through these strings.

              This completer uses the tags corrections and original when generating the possible corrections and
              the  original  string.   The format style for the former may contain the additional sequences `%e'
              and `%o' which will be replaced by the number of errors accepted to generate the  corrections  and
              the original string, respectively.

              The  completer  progressively  increases  the  number  of  errors  allowed  up to the limit by the
              max-errors style, hence if a completion is found with one error, no completions  with  two  errors
              will be shown, and so on.  It modifies the completer name in the context to indicate the number of
              errors  being  tried: on the first try the completer field contains `approximate-1', on the second
              try `approximate-2', and so on.

              When _approximate is called from another function, the number of errors to accept  may  be  passed
              with  the  -a  option.   The  argument  is  in the same format as the max-errors style, all in one
              string.

              Note that this completer (and the _correct completer mentioned below) can be  quite  expensive  to
              call,  especially  when  a large number of errors are allowed.  One way to avoid this is to set up
              the completer style using the -e option to zstyle so that  some  completers  are  only  used  when
              completion is attempted a second time on the same string, e.g.:

                     zstyle -e ':completion:*' completer '
                       if [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
                         _last_try="$HISTNO$BUFFER$CURSOR"
                         reply=(_complete _match _prefix)
                       else
                         reply=(_ignored _correct _approximate)
                       fi'

              This  uses  the  HISTNO  parameter and the BUFFER and CURSOR special parameters that are available
              inside zle and completion widgets to find out if the command line hasn't changed  since  the  last
              time  completion  was  tried.   Only  then  are the _ignored, _correct and _approximate completers
              called.

       _canonical_paths [ -A var ] [ -N ] [ -MJV12nfX ] tag descr [ paths ... ]
              This completion function completes all paths given to it, and  also  tries  to  offer  completions
              which  point  to  the  same file as one of the paths given (relative path when an absolute path is
              given, and vice versa; when ..'s are present in the word to be completed; and some paths got  from
              symlinks).

              -A,  if  specified, takes the paths from the array variable specified. Paths can also be specified
              on the command line as shown above.  -N, if specified, prevents  canonicalizing  the  paths  given
              before using them for completion, in case they are already so. The options -M, -J, -V, -1, -2, -n,
              -F, -X are passed to compadd.

              See _description for a description of tag and descr.

       _cmdambivalent
              Completes the remaining positional arguments as an external command.  The external command and its
              arguments   are   completed  as  separate  arguments  (in  a  manner  appropriate  for  completing
              /usr/bin/env) if there are two or more remaining positional arguments on the command line, and  as
              a  quoted  command  string  (in  the  manner  of  system(...)) otherwise.  See also _cmdstring and
              _precommand.

              This function takes no arguments.

       _cmdstring
              Completes an external command as a single argument, as for system(...).

       _complete
              This completer generates all possible completions in a context-sensitive manner,  i.e.  using  the
              settings defined with the compdef function explained above and the current settings of all special
              parameters.  This gives the normal completion behaviour.

              To  complete  arguments of commands, _complete uses the utility function _normal, which is in turn
              responsible for finding the particular function; it is described below.  Various contexts  of  the
              form  -context-  are  handled specifically. These are all mentioned above as possible arguments to
              the #compdef tag.

              Before trying to find a function for  a  specific  context,  _complete  checks  if  the  parameter
              `compcontext'  is  set.  Setting  `compcontext'  allows  the  usual  completion  dispatching to be
              overridden which is useful in places such as a function that uses vared for input. If it is set to
              an array, the elements are taken to be the possible matches which will be completed using the  tag
              `values'  and  the description `value'. If it is set to an associative array, the keys are used as
              the possible completions and the values (if non-empty) are used as descriptions for  the  matches.
              If   `compcontext'   is   set   to   a  string  containing  colons,  it  should  be  of  the  form
              `tag:descr:action'.  In this case the tag and descr give the tag and description to  use  and  the
              action  indicates  what should be completed in one of the forms accepted by the _arguments utility
              function described below.

              Finally, if `compcontext' is set to a string without colons, the value is taken as the name of the
              context to use and the function defined for that context will be called.  For this purpose,  there
              is  a  special context named -command-line- that completes whole command lines (commands and their
              arguments).  This is not used by the completion system itself  but  is  nonetheless  handled  when
              explicitly called.

       _correct
              Generate  corrections,  but not completions, for the current word; this is similar to _approximate
              but will not allow any number of extra characters at the  cursor  as  that  completer  does.   The
              effect  is similar to spell-checking.  It is based on _approximate, but the completer field in the
              context name is correct.

              For example, with:

                     zstyle ':completion:::::' completer \
                            _complete _correct _approximate
                     zstyle ':completion:*:correct:::' max-errors 2 not-numeric
                     zstyle ':completion:*:approximate:::' max-errors 3 numeric

              correction will accept up to two errors.  If a numeric argument is given, correction will  not  be
              performed,  but  correcting  completion  will  be,  and will accept as many errors as given by the
              numeric argument.  Without a numeric argument, first correction  and  then  correcting  completion
              will be tried, with the first one accepting two errors and the second one accepting three errors.

              When  _correct  is called as a function, the number of errors to accept may be given following the
              -a option.  The argument is in the same form a values to the accept style, all in one string.

              This completer function is intended to be used without the _approximate completer or,  as  in  the
              example,  just before it.  Using it after the _approximate completer is useless since _approximate
              will at least generate the corrected strings generated by the _correct completer --  and  probably
              more.

       _expand
              This  completer function does not really perform completion, but instead checks if the word on the
              command line is eligible for expansion and, if  it  is,  gives  detailed  control  over  how  this
              expansion  is  done.   For  this  to  happen,  the  completion  system  needs  to  be invoked with
              complete-word, not expand-or-complete (the default binding for TAB), as otherwise the string  will
              be  expanded by the shell's internal mechanism before the completion system is started.  Note also
              this completer should be called before the _complete completer function.

              The tags used when generating expansions are all-expansions for the string containing all possible
              expansions, expansions when adding the possible expansions as single  matches  and  original  when
              adding  the  original string from the line.  The order in which these strings are generated, if at
              all, can be controlled by the group-order and tag-order styles, as usual.

              The format string for all-expansions and for expansions may contain the sequence `%o'  which  will
              be replaced by the original string from the line.

              The  kind  of  expansion  to  be  tried is controlled by the substitute, glob and subst-globs-only
              styles.

              It is also possible to call _expand as a function, in  which  case  the  different  modes  may  be
              selected with options: -s for substitute, -g for glob and -o for subst-globs-only.

       _expand_alias
              If  the word the cursor is on is an alias, it is expanded and no other completers are called.  The
              types of aliases which are to be expanded can be controlled with the styles  regular,  global  and
              disabled.

              This function is also a bindable command, see the section `Bindable Commands' below.

       _extensions
              If the cursor follows the string `*.', filename extensions are completed. The extensions are taken
              from files in current directory or a directory specified at the beginning of the current word. For
              exact  matches,  completion  continues  to  allow  other  completers such as _expand to expand the
              pattern. The standard add-space and prefix-hidden styles are observed.

       _external_pwds
              Completes current directories of other zsh processes belonging to the current user.

              This is intended to be used via _generic, bound to a custom key  combination.  Note  that  pattern
              matching is enabled so matching is performed similar to how it works with the _match completer.

       _history
              Complete  words  from  the  shell's  command   history.   This  completer can be controlled by the
              remove-all-dups, and sort styles as for  the  _history_complete_word  bindable  command,  see  the
              section `Bindable Commands' below and the section `Completion System Configuration' above.

       _ignored
              The  ignored-patterns  style  can be set to a list of patterns which are compared against possible
              completions; matching ones are removed.  With this completer those matches can be  reinstated,  as
              if  no ignored-patterns style were set.  The completer actually generates its own list of matches;
              which completers are invoked is determined in the same way as  for  the  _prefix  completer.   The
              single-ignored style is also available as described above.

       _list  This  completer  allows  the  insertion  of  matches to be delayed until completion is attempted a
              second time without the word on the line being changed.  On the first attempt, only  the  list  of
              matches  will  be  shown.   It  is  affected  by  the  styles  condition and word, see the section
              `Completion System Configuration' above.

       _match This completer is intended to be used after the _complete completer.  It behaves similarly but the
              string on the command line may be a pattern to match against trial completions.   This  gives  the
              effect of the GLOB_COMPLETE option.

              Normally  completion will be performed by taking the pattern from the line, inserting a `*' at the
              cursor position and comparing the resulting pattern with the possible completions generated.  This
              can be modified with the match-original style described above.

              The generated matches will be offered in a menu completion unless the insert-unambiguous style  is
              set to `true'; see the description above for other options for this style.

              Note  that matcher specifications defined globally or used by the completion functions (the styles
              matcher-list and matcher) will not be used.

       _menu  This completer was written as simple example function to show how menu completion can  be  enabled
              in  shell code. However, it has the notable effect of disabling menu selection which can be useful
              with _generic based widgets. It should be used as the first completer in the list.  Note that this
              is independent of the setting of the MENU_COMPLETE option and does not work with  the  other  menu
              completion widgets such as reverse-menu-complete, or accept-and-menu-complete.

       _oldlist
              This  completer controls how the standard completion widgets behave when there is an existing list
              of completions which may have been generated by a  special  completion  (i.e.  a  separately-bound
              completion  command).   It  allows  the  ordinary  completion  keys to continue to use the list of
              completions thus generated, instead of producing a new list of  ordinary  contextual  completions.
              It  should  appear in the list of completers before any of the widgets which generate matches.  It
              uses two styles: old-list and old-menu, see the section `Completion System Configuration' above.

       _precommand
              Complete an external command in word-separated arguments, as for exec and /usr/bin/env.

       _prefix
              This completer can be used to try  completion  with  the  suffix  (everything  after  the  cursor)
              ignored.   In  other  words, the suffix will not be considered to be part of the word to complete.
              The effect is similar to the expand-or-complete-prefix command.

              The completer style is used to decide which other completers are to be called to generate matches.
              If this style is unset, the list of completers set for the current context is used --  except,  of
              course,  the  _prefix  completer itself.  Furthermore, if this completer appears more than once in
              the list of completers only those completers not already tried by the last invocation  of  _prefix
              will be called.

              For example, consider this global completer style:

                     zstyle ':completion:*' completer \
                         _complete _prefix _correct _prefix:foo

              Here,  the  _prefix  completer  tries  normal completion but ignoring the suffix.  If that doesn't
              generate any matches, and neither does the call to the _correct completer after it,  _prefix  will
              be  called  a  second time and, now only trying correction with the suffix ignored.  On the second
              invocation the completer part of the context appears as `foo'.

              To use _prefix as the last resort and try only normal completion when it is invoked:

                     zstyle ':completion:*' completer _complete ... _prefix
                     zstyle ':completion::prefix:*' completer _complete

              The add-space style is also respected.  If it is set to `true' then _prefix will  insert  a  space
              between the matches generated (if any) and the suffix.

              Note  that  this  completer  is  only useful if the COMPLETE_IN_WORD option is set; otherwise, the
              cursor will be moved to the end of the current word before the completion code is called and hence
              there will be no suffix.

       _user_expand
              This completer behaves similarly to the _expand completer but instead performs expansions  defined
              by  users.  The styles add-space and sort styles specific to the _expand completer are usable with
              _user_expand in addition to other styles handled more generally by the completion system.  The tag
              all-expansions is also available.

              The expansion depends on the array style  user-expand  being  defined  for  the  current  context;
              remember  that  the context for completers is less specific than that for contextual completion as
              the full context has not yet been determined.  Elements of the array may have one of the following
              forms:

              $hash

                     hash is the name of an associative array.  Note this is not a  full  parameter  expression,
                     merely  a  $,  suitably  quoted  to prevent immediate expansion, followed by the name of an
                     associative array.  If the trial expansion word  matches  a  key  in  hash,  the  resulting
                     expansion is the corresponding value.
              _func

                     _func  is  the  name  of a shell function whose name must begin with _ but is not otherwise
                     special to the completion system.  The function  is  called  with  the  trial  word  as  an
                     argument.  If the word is to be expanded, the function should set the array reply to a list
                     of  expansions.   Optionally, it can set REPLY to a word that will be used as a description
                     for the set of expansions.  The return status of the function is irrelevant.

BINDABLE COMMANDS

       In addition to the context-dependent completions provided, which are expected to work in  an  intuitively
       obvious  way,  there  are  a  few widgets implementing special behaviour which can be bound separately to
       keys.  The following is a list of these and their default bindings.

       _bash_completions
              This function is used by two widgets, _bash_complete-word and _bash_list-choices.   It  exists  to
              provide  compatibility  with  completion  bindings  in  bash.   The  last character of the binding
              determines what is completed: `!', command names; `$', environment  variables;  `@',  host  names;
              `/',  file  names;  `~'  user  names.  In bash, the binding preceded by `\e' gives completion, and
              preceded by `^X' lists options.  As some of these bindings clash with standard zsh bindings,  only
              `\e~'  and  `^X~'  are bound by default.  To add the rest, the following should be added to .zshrc
              after compinit has been run:

                     for key in '!' '$' '@' '/' '~'; do
                       bindkey "\e$key" _bash_complete-word
                       bindkey "^X$key" _bash_list-choices
                     done

              This includes the bindings for `~' in  case  they  were  already  bound  to  something  else;  the
              completion code does not override user bindings.

       _correct_filename (^XC)
              Correct  the filename path at the cursor position.  Allows up to six errors in the name.  Can also
              be called with an argument to correct a filename path, independently of  zle;  the  correction  is
              printed on standard output.

       _correct_word (^Xc)
              Performs  correction  of  the  current argument using the usual contextual completions as possible
              choices. This stores the string `correct-word' in the function field of the context name and  then
              calls the _correct completer.

       _expand_alias (^Xa)
              This  function  can  be  used  as  a completer and as a bindable command.  It expands the word the
              cursor is on if it is an alias.  The types of alias expanded can be  controlled  with  the  styles
              regular, global and disabled.

              When  used  as  a bindable command there is one additional feature that can be selected by setting
              the complete style to `true'.   In  this  case,  if  the  word  is  not  the  name  of  an  alias,
              _expand_alias tries to complete the word to a full alias name without expanding it.  It leaves the
              cursor  directly after the completed word so that invoking _expand_alias once more will expand the
              now-complete alias name.

       _expand_word (^Xe)
              Performs expansion on the current word:  equivalent to the standard expand-word command, but using
              the _expand completer.   Before  calling  it,  the  function  field  of  the  context  is  set  to
              `expand-word'.

       _generic
              This  function  is  not  defined as a widget and not bound by default.  However, it can be used to
              define a widget and will then store the name of the widget in the function field  of  the  context
              and call the completion system.  This allows custom completion widgets with their own set of style
              settings  to  be  defined easily.  For example, to define a widget that performs normal completion
              and starts menu selection:

                     zle -C foo complete-word _generic
                     bindkey '...' foo
                     zstyle ':completion:foo:*' menu yes select=1

              Note in particular that the completer style may be set for the context in order to change the  set
              of  functions  used to generate possible matches.  If _generic is called with arguments, those are
              passed through to _main_complete as the list of completers  in  place  of  those  defined  by  the
              completer style.

       _history_complete_word (\e/)
              Complete  words  from  the shell's command history. This uses the list, remove-all-dups, sort, and
              stop styles.

       _most_recent_file (^Xm)
              Complete the name of the most recently modified file matching the  pattern  on  the  command  line
              (which  may  be  blank).   If  given a numeric argument N, complete the Nth most recently modified
              file.  Note the completion, if any, is always unique.

       _next_tags (^Xn)
              This command alters the set of matches used to that for the next tag, or set of  tags,  either  as
              given by the tag-order style or as set by default; these matches would otherwise not be available.
              Successive invocations of the command cycle through all possible sets of tags.

       _read_comp (^X^R)
              Prompt  the  user for a string, and use that to perform completion on the current word.  There are
              two possibilities for the string.  First, it can be a set of  words  beginning  `_',  for  example
              `_files  -/',  in  which  case  the  function  with  any  arguments will be called to generate the
              completions.  Unambiguous parts of the function  name  will  be  completed  automatically  (normal
              completion is not available at this point) until a space is typed.

              Second,  any  other  string will be passed as a set of arguments to compadd and should hence be an
              expression specifying what should be completed.

              A very restricted set of editing commands is available when reading the string:   `DEL'  and  `^H'
              delete  the  last  character;  `^U'  deletes the line, and `^C' and `^G' abort the function, while
              `RET' accepts the completion.  Note the string is used verbatim as a command  line,  so  arguments
              must be quoted in accordance with standard shell rules.

              Once  a  string has been read, the next call to _read_comp will use the existing string instead of
              reading a new one.  To force a new string to be read, call _read_comp with a numeric argument.

       _complete_debug (^X?)
              This widget performs ordinary completion, but captures in a temporary file a trace  of  the  shell
              commands executed by the completion system.  Each completion attempt gets its own file.  A command
              to view each of these files is pushed onto the editor buffer stack.

       _complete_help (^Xh)
              This  widget  displays information about the context names, the tags, and the completion functions
              used when completing at the current cursor position. If given a numeric argument other than 1  (as
              in `ESC-2 ^Xh'), then the styles used and the contexts for which they are used will be shown, too.

              Note  that the information about styles may be incomplete; it depends on the information available
              from the completion functions called, which in turn is determined by the  user's  own  styles  and
              other settings.

       _complete_help_generic
              Unlike  other  commands  listed  here,  this  must be created as a normal ZLE widget rather than a
              completion widget (i.e. with zle -N).  It is used for generating help with a widget bound  to  the
              _generic widget that is described above.

              If  this widget is created using the name of the function, as it is by default, then when executed
              it will read a key sequence.  This is expected to be bound to a call to a completion function that
              uses the _generic widget.  That widget will be executed, and  information  provided  in  the  same
              format that the _complete_help widget displays for contextual completion.

              If   the   widget's   name   contains   debug,   for   example   if  it  is  created  as  `zle  -N
              _complete_debug_generic _complete_help_generic', it will read and  execute  the  keystring  for  a
              generic  widget  as before, but then generate debugging information as done by _complete_debug for
              contextual completion.

              If the widget's name contains noread, it will not read a keystring but instead  arrange  that  the
              next use of a generic widget run in the same shell will have the effect as described above.

              The  widget  works  by  setting  the  shell  parameter  ZSH_TRACE_GENERIC_WIDGET  which is read by
              _generic.  Unsetting the parameter cancels any pending effect of the noread form.

              For example, after executing the following:

                     zle -N _complete_debug_generic _complete_help_generic
                     bindkey '^x:' _complete_debug_generic

              typing `C-x :' followed by the key sequence for a generic widget will cause trace output for  that
              widget to be saved to a file.

       _complete_tag (^Xt)
              This  widget  completes  symbol  tags  created  by the etags or ctags programmes (note there is no
              connection with the completion system's tags) stored in a file TAGS, in the format used by  etags,
              or  tags,  in  the format created by ctags.  It will look back up the path hierarchy for the first
              occurrence of either file; if both exist, the file TAGS is preferred.  You can  specify  the  full
              path  to  a  TAGS  or tags file by setting the parameter $TAGSFILE or $tagsfile respectively.  The
              corresponding completion tags used are etags and vtags, after emacs and vi respectively.

UTILITY FUNCTIONS

       Descriptions follow for utility functions that may be  useful  when  writing  completion  functions.   If
       functions  are  installed  in  subdirectories,  most  of these reside in the Base subdirectory.  Like the
       example functions for commands in the distribution, the utility functions generating matches  all  follow
       the  convention  of  returning  status  zero  if  they  generated completions and non-zero if no matching
       completions could be added.

       _absolute_command_paths
              This function completes external commands  as  absolute  paths  (unlike  _command_names  -e  which
              completes their basenames).  It takes no arguments.

       _all_labels [ -x ] [ -12VJ ] tag name descr [ command arg ... ]
              This  is  a convenient interface to the _next_label function below, implementing the loop shown in
              the _next_label example.  The command and its arguments are called to generate the  matches.   The
              options  stored  in  the parameter name will automatically be inserted into the args passed to the
              command.  Normally, they are put directly after the command, but if one of the args  is  a  single
              hyphen,  they  are  inserted directly before that.  If the hyphen is the last argument, it will be
              removed from the argument list before the command is called.  This allows _all_labels to  be  used
              in  almost  all  cases  where the matches can be generated by a single call to the compadd builtin
              command or by a call to one of the utility functions.

              For example:

                     local expl
                     ...
                     if _requested foo; then
                       ...
                       _all_labels foo expl '...' compadd ... - $matches
                     fi

              Will complete the strings from the matches parameter, using compadd with additional options  which
              will take precedence over those generated by _all_labels.

       _alternative [ -O name ] [ -C name ] spec ...
              This  function  is  useful  in  simple  cases  where  multiple tags are available.  Essentially it
              implements a loop like the one described for the _tags function below.

              The tags to use and the action to perform if a tag is requested  are  described  using  the  specs
              which  are  of  the  form: `tag:descr:action'.  The tags are offered using _tags and if the tag is
              requested, the action is executed with  the  given  description  descr.   The  actions  are  those
              accepted by the _arguments function (described below), excluding the `->state' and `=...' forms.

              For example, the action may be a simple function call:

                     _alternative \
                         'users:user:_users' \
                         'hosts:host:_hosts'

              offers  usernames  and hostnames as possible matches, generated by the _users and _hosts functions
              respectively.

              Like _arguments, this function uses _all_labels to execute the actions, which will loop  over  all
              sets  of tags.  Special handling is only required if there is an additional valid tag, for example
              inside a function called from _alternative.

              The option `-O name' is used in the same way as by the _arguments function.  In other  words,  the
              elements of the name array will be passed to compadd when executing an action.

              Like  _tags this function supports the -C option to give a different name for the argument context
              field.

       _arguments [ -nswWCRS ] [ -A pat ] [ -O name ] [ -M matchspec ]
                  [ : ] spec ...
       _arguments [ opt ... ] -- [ -l ] [ -i pats ] [ -s pair ]
                  [ helpspec ...]
              This function can be used to give a complete specification for  completion  for  a  command  whose
              arguments follow standard UNIX option and argument conventions.

              Options Overview

              Options  to  _arguments  itself  must  be in separate words, i.e. -s -w, not -sw.  The options are
              followed by specs that  describe  options  and  arguments  of  the  analyzed  command.   To  avoid
              ambiguity,  all  options  to  _arguments  itself  may be separated from the spec forms by a single
              colon.

              The `--' form is used to intuit spec forms from the help output of the command being analyzed, and
              is described in detail below.  The opts for the `--' form are otherwise the same  options  as  the
              first  form.   Note  that `-s' following `--' has a distinct meaning from `-s' preceding `--', and
              both may appear.

              The option switches -s, -S, -A, -w, and -W affect  how  _arguments  parses  the  analyzed  command
              line's options.  These switches are useful for commands with standard argument parsing.

              The options of _arguments have the following meanings:

              -n     With this option, _arguments sets the parameter NORMARG to the position of the first normal
                     argument  in  the  $words  array,  i.e. the position after the end of the options.  If that
                     argument has not been reached, NORMARG is set to -1.  The caller  should  declare  `integer
                     NORMARG' if the -n option is passed; otherwise the parameter is not used.

              -s     Enable  option  stacking  for single-letter options, whereby multiple single-letter options
                     may be combined into a single word.  For example, the two options  `-x'  and  `-y'  may  be
                     combined  into  a single word `-xy'.  By default, every word corresponds to a single option
                     name (`-xy' is a single option named `xy').

                     Options beginning with a single hyphen or  plus  sign  are  eligible  for  stacking;  words
                     beginning with two hyphens are not.

                     Note  that -s after -- has a different meaning, which is documented in the segment entitled
                     `Deriving spec forms from the help output'.

              -w     In combination with -s, allow option stacking even if one  or  more  of  the  options  take
                     arguments.   For  example,  if  -x  takes an argument, with no -s, `-xy' is considered as a
                     single (unhandled) option; with -s, -xy is an option with the argument `y';  with  both  -s
                     and -w, -xy is the option -x and the option -y with arguments to -x (and to -y, if it takes
                     arguments) still to come in subsequent words.

              -W     This  option  takes  -w  a stage further:  it is possible to complete single-letter options
                     even after an argument that occurs in the same word.  However, it  depends  on  the  action
                     performed  whether options will really be completed at this point.  For more control, use a
                     utility function like _guard as part of the action.

              -C     Modify the curcontext parameter for an action of the form `->state'.  This is discussed  in
                     detail below.

              -R     Return status 300 instead of zero when a $state is to be handled, in the `->string' syntax.

              -S     Do  not  complete  options  after  a  `--' appearing on the line, and ignore the `--'.  For
                     example, with -S, in the line

                            foobar -x -- -y

                     the `-x' is considered an option, the `-y' is considered  an  argument,  and  the  `--'  is
                     considered to be neither.

              -A pat Do  not complete options after the first non-option argument on the line.  pat is a pattern
                     matching all strings which are not  to  be  taken  as  arguments.   For  example,  to  make
                     _arguments  stop  completing  options  after  the  first  normal argument, but ignoring all
                     strings starting with a hyphen even if they are not described by one of the  optspecs,  the
                     form is `-A "-*"'.

              -O name
                     Pass  the  elements  of the array name as arguments to functions called to execute actions.
                     This is discussed in detail below.

              -M matchspec
                     Use the match specification matchspec for completing option names and values.  The  default
                     matchspec  allows  partial  word completion after `_' and `-', such as completing `-f-b' to
                     `-foo-bar'.  The default matchspec is:
                     r:|[_-]=* r:|=*

              specs: overview

              Each of the following forms is a spec describing individual sets of options or  arguments  on  the
              command line being analyzed.

              n:message:action
              n::message:action
                     This  describes  the  n'th  normal argument.  The message will be printed above the matches
                     generated and the action indicates what can be completed in this position (see below).   If
                     there  are two colons before the message the argument is optional.  If the message contains
                     only white space, nothing will be printed above the  matches  unless  the  action  adds  an
                     explanation string itself.

              :message:action
              ::message:action
                     Similar,  but  describes  the  next  argument,  whatever number that happens to be.  If all
                     arguments are specified in this form in the correct order the numbers are unnecessary.

              *:message:action
              *::message:action
              *:::message:action
                     This describes how arguments (usually non-option arguments, those not beginning with  -  or
                     +)  are  to  be  completed when neither of the first two forms was provided.  Any number of
                     arguments can be completed in this fashion.

                     With two colons before the message,  the  words  special  array  and  the  CURRENT  special
                     parameter are modified to refer only to the normal arguments when the action is executed or
                     evaluated.   With  three  colons  before the message they are modified to refer only to the
                     normal arguments covered by this description.

              optspec
              optspec:...
                     This describes an option.  The colon indicates handling for one or more  arguments  to  the
                     option; if it is not present, the option is assumed to take no arguments.

                     The  following  forms  are available for the initial optspec, whether or not the option has
                     arguments.

                     *optspec
                            Here optspec is one of the remaining forms  below.   This  indicates  the  following
                            optspec  may  be repeated.  Otherwise if the corresponding option is already present
                            on the command line to the left of the cursor it will not be offered again.

                     -optname
                     +optname
                            In the simplest form the optspec is just the option name beginning with a minus or a
                            plus sign, such as `-foo'.  The first argument for the option (if any)  must  follow
                            as a separate word directly after the option.

                            Either  of  `-+optname'  and  `+-optname'  can  be used to specify that -optname and
                            +optname are both valid.

                            In all the remaining forms, the leading `-' may be replaced by or paired with `+' in
                            this way.

                     -optname-
                            The first argument of the option must come directly after the  option  name  in  the
                            same  word.   For  example,  `-foo-:...'  specifies  that  the  completed option and
                            argument will look like `-fooarg'.

                     -optname+
                            The first argument may appear immediately after optname in the  same  word,  or  may
                            appear as a separate word after the option.  For example, `-foo+:...' specifies that
                            the completed option and argument will look like either `-fooarg' or `-foo arg'.

                     -optname=
                            The  argument  may  appear  as  the  next  word,  or in same word as the option name
                            provided that it is separated from it by an equals sign, for example  `-foo=arg'  or
                            `-foo arg'.

                     -optname=-
                            The  argument  to  the option must appear after an equals sign in the same word, and
                            may not be given in the next argument.

                     optspec[explanation]
                            An explanation string may be appended to any of the preceding forms  of  optspec  by
                            enclosing it in brackets, as in `-q[query operation]'.

                            The  verbose  style  is used to decide whether the explanation strings are displayed
                            with the option in a completion listing.

                            If no bracketed explanation string is given but the auto-description  style  is  set
                            and  only  one  argument  is  described  for this optspec, the value of the style is
                            displayed, with any appearance of the sequence `%d' in it replaced by the message of
                            the first optarg that follows the optspec; see below.

                     It is possible for options with a literal `+' or `=' to appear, but that character must  be
                     quoted, for example `-\+'.

                     Each optarg following an optspec must take one of the following forms:

                     :message:action
                     ::message:action
                            An argument to the option; message and action are treated as for ordinary arguments.
                            In the first form, the argument is mandatory, and in the second form it is optional.

                            This  group  may  be  repeated  for options which take multiple arguments.  In other
                            words,  :message1:action1:message2:action2  specifies  that  the  option  takes  two
                            arguments.

                     :*pattern:message:action
                     :*pattern::message:action
                     :*pattern:::message:action
                            This  describes  multiple  arguments.   Only  the  last  optarg for an option taking
                            multiple arguments may be given in this form.  If the pattern is empty  (i.e.  :*:),
                            all  the remaining words on the line are to be completed as described by the action;
                            otherwise, all the words up to and including a word matching the pattern are  to  be
                            completed using the action.

                            Multiple  colons  are treated as for the `*:...' forms for ordinary arguments:  when
                            the message is preceded by two colons, the  words  special  array  and  the  CURRENT
                            special  parameter  are modified during the execution or evaluation of the action to
                            refer only to the words after the option.  When preceded by three colons,  they  are
                            modified to refer only to the words covered by this description.

              Any literal colon in an optname, message, or action must be preceded by a backslash, `\:'.

              Each  of  the  forms  above  may be preceded by a list in parentheses of option names and argument
              numbers.  If the given option is on the command line,  the  options  and  arguments  indicated  in
              parentheses  will  not  be  offered.   For example, `(-two -three 1)-one:...' completes the option
              `-one'; if this appears on the command line, the options -two and -three and  the  first  ordinary
              argument  will not be completed after it.  `(-foo):...' specifies an ordinary argument completion;
              -foo will not be completed if that argument is already present.

              Other items may appear in the list of excluded options to indicate various other items that should
              not be applied when the current specification is matched: a single star (*) for the rest arguments
              (i.e. a specification of the form `*:...'); a colon (:) for all  normal  (non-option-)  arguments;
              and  a  hyphen (-) for all options.  For example, if `(*)' appears before an option and the option
              appears on the command line, the list of remaining arguments  (those  shown  in  the  above  table
              beginning with `*:') will not be completed.

              To aid in reuse of specifications, it is possible to precede any of the forms above with `!'; then
              the  form  will  no longer be completed, although if the option or argument appears on the command
              line they will be skipped as normal.  The main use for this is when the arguments are given by  an
              array,  and  _arguments  is  called  repeatedly  for  more  specific  contexts:  on the first call
              `_arguments $global_options' is used, and on subsequent calls `_arguments !$^global_options'.

              specs: actions

              In each of the forms above the action determines how completions should be generated.  Except  for
              the  `->string'  form  below,  the  action will be executed by calling the _all_labels function to
              process all tag labels.  No special handling of tags is needed unless a function call introduces a
              new one.

              The functions called to execute actions will be called with the elements of the array named by the
              `-O name' option as arguments.  This can be used, for example, to pass the same set of options for
              the compadd builtin to all actions.

              The forms for action are as follows.

               (single unquoted space)
                     This is useful where an argument is required  but  it  is  not  possible  or  desirable  to
                     generate  matches  for  it.  The message will be displayed but no completions listed.  Note
                     that even in this case the colon at the end of the  message  is  needed;  it  may  only  be
                     omitted when neither a message nor an action is given.

              (item1 item2 ...)
                     One of a list of possible matches, for example:

                            :foo:(foo bar baz)

              ((item1\:desc1 ...))
                     Similar  to  the  above, but with descriptions for each possible match.  Note the backslash
                     before the colon.  For example,

                            :foo:((a\:bar b\:baz))

                     The matches will be listed together with their descriptions if the description style is set
                     with the values tag in the context.

              ->string
                     In this form, _arguments processes the arguments and options and then  returns  control  to
                     the  calling  function with parameters set to indicate the state of processing; the calling
                     function then  makes  its  own  arrangements  for  generating  completions.   For  example,
                     functions that implement a state machine can use this type of action.

                     Where  _arguments encounters action in the `->string' format, it will strip all leading and
                     trailing whitespace from string and set the array state to the set of all strings for which
                     an action is to be performed.  The elements of  the  array  state_descr  are  assigned  the
                     corresponding message field from each optarg containing such an action.

                     By  default  and  in  common  with  all other well behaved completion functions, _arguments
                     returns status zero if it was able to add matches and non-zero otherwise. However,  if  the
                     -R  option is given, _arguments will instead return a status of 300 to indicate that $state
                     is to be handled.

                     In addition to  $state  and  $state_descr,  _arguments  also  sets  the  global  parameters
                     `context', `line' and `opt_args' as described below, and does not reset any changes made to
                     the  special  parameters  such  as  PREFIX  and words.  This gives the calling function the
                     choice of resetting these parameters or propagating changes in them.

                     A function calling _arguments with  at  least  one  action  containing  a  `->string'  must
                     therefore declare appropriate local parameters:

                            local context state state_descr line
                            typeset -A opt_args

                     to prevent _arguments from altering the global environment.

              {eval-string}
                     A  string  in  braces  is  evaluated as shell code to generate matches.  If the eval-string
                     itself does not begin with an opening parenthesis or brace it is split into separate  words
                     before execution.

              = action
                     If the action starts with `= ' (an equals sign followed by a space), _arguments will insert
                     the  contents  of the argument field of the current context as the new first element in the
                     words special array and increment the value of the CURRENT special parameter.  This has the
                     effect of inserting a dummy word onto the completion command line while  not  changing  the
                     point at which completion is taking place.

                     This  is most useful with one of the specifiers that restrict the words on the command line
                     on which the action is to operate (the two- and three-colon forms above).   One  particular
                     use  is  when  an action itself causes _arguments on a restricted range; it is necessary to
                     use this trick to insert an appropriate command name into the range for the second call  to
                     _arguments to be able to parse the line.

               word...
              word...
                     This  covers  all  forms  other  than  those above.  If the action starts with a space, the
                     remaining list of words will be invoked unchanged.

                     Otherwise it will be invoked with some extra strings placed after the first word; these are
                     to be passed down as options to the compadd builtin.  They ensure that the state  specified
                     by _arguments, in particular the descriptions of options and arguments, is correctly passed
                     to  the  completion command.  These additional arguments are taken from the array parameter
                     `expl'; this will be set up before executing the action and hence may be referred to inside
                     it, typically in an expansion of the form `$expl[@]' which preserves empty elements of  the
                     array.

              During the performance of the action the array `line' will be set to the normal arguments from the
              command  line,  i.e.  the words from the command line after the command name excluding all options
              and their arguments.  Options are stored in the associative array `opt_args' with option names  as
              keys  and  their  arguments as the values.  For options that have more than one argument these are
              given as one string, separated by colons.  All colons and backslashes in  the  original  arguments
              are preceded with backslashes.

              The  parameter `context' is set when returning to the calling function to perform an action of the
              form `->string'.  It is set to an array of elements corresponding to the elements of $state.  Each
              element is a suitable name for the argument field of the context: either  a  string  of  the  form
              `option-opt-n'  for the n'th argument of the option -opt, or a string of the form `argument-n' for
              the n'th argument.  For `rest' arguments, that is those in the list at  the  end  not  handled  by
              position, n is the string `rest'.  For example, when completing the argument of the -o option, the
              name is `option-o-1', while for the second normal (non-option-) argument it is `argument-2'.

              Furthermore,  during  the evaluation of the action the context name in the curcontext parameter is
              altered to append the same string that is stored in the context parameter.

              The option -C tells _arguments to modify the curcontext  parameter  for  an  action  of  the  form
              `->state'.   This  is  the  standard parameter used to keep track of the current context.  Here it
              (and not the context array) should be made local to the calling function to avoid passing back the
              modified value and should be initialised to the current value at the start of the function:

                     local curcontext="$curcontext"

              This is useful where it is not possible for multiple states to be valid together.

              Grouping Options

              Options can be grouped to simplify exclusion lists. A group is introduced with `+' followed  by  a
              name  for  the  group  in the subsequent word. Whole groups can then be referenced in an exclusion
              list or a group name can be used to disambiguate  between  two  forms  of  the  same  option.  For
              example:

                     _arguments \
                         '(group2--x)-a' \
                       + group1 \
                         -m \
                         '(group2)-n' \
                       + group2 \
                         -x -y

              If  the name of a group is specified in the form `(name)' then only one value from that group will
              ever be completed;  more  formally,  all  specifications  are  mutually  exclusive  to  all  other
              specifications in that group. This is useful for defining options that are aliases for each other.
              For example:

                     _arguments \
                         -a -b \
                       + '(operation)' \
                         {-c,--compress}'[compress]' \
                         {-d,--decompress}'[decompress]' \
                         {-l,--list}'[list]'

              If  an  option  in  a  group  appears  on  the command line, it is stored in the associative array
              `opt_args' with 'group-option' as a key.  In the example above, a key `operation--c'  is  used  if
              the option `-c' is present on the command line.

              Specifying Multiple Sets of Arguments

              It is possible to specify multiple sets of options and arguments with the sets separated by single
              hyphens.  This  differs  from  groups in that sets are considered to be mutually exclusive of each
              other.

              Specifications before the first set and from any group are common to all sets. For example:

                     _arguments \
                         -a \
                       - set1 \
                         -c \
                       - set2 \
                         -d \
                         ':arg:(x2 y2)'

              This defines two sets.  When the command line contains the option `-c', the `-d'  option  and  the
              argument  will  not be considered possible completions.  When it contains `-d' or an argument, the
              option `-c' will not be considered.  However, after `-a' both sets will still be considered valid.

              As for groups, the name of a set may appear in exclusion lists, either alone or preceding a normal
              option or argument specification.

              The completion code has to parse the command line separately for each set. This  can  be  slow  so
              sets  should  only  be used when necessary.  A useful alternative is often an option specification
              with rest-arguments (as in `-foo:*:...'); here the option -foo swallows up all remaining arguments
              as described by the optarg definitions.

              Deriving spec forms from the help output

              The option `--' allows _arguments to work out the names of long options that support the  `--help'
              option  which  is  standard  in  many  GNU commands.  The command word is called with the argument
              `--help' and the output examined for option names.  Clearly, it can be dangerous to pass  this  to
              commands which may not support this option as the behaviour of the command is unspecified.

              In  addition  to  options, `_arguments --' will try to deduce the types of arguments available for
              options when the form `--opt=val' is valid.  It is also possible to provide hints by examining the
              help text of the command and adding helpspec of the form `pattern:message:action'; note that other
              _arguments spec forms are not used.  The pattern is matched against the help text for  an  option,
              and  if  it matches the message and action are used as for other argument specifiers.  The special
              case of `*:' means both message and action are empty, which has  the  effect  of  causing  options
              having  no  description  in the help output to be ordered in listings ahead of options that have a
              description.

              For example:

                     _arguments -- '*\*:toggle:(yes no)' \
                                   '*=FILE*:file:_files' \
                                   '*=DIR*:directory:_files -/' \
                                   '*=PATH*:directory:_files -/'

              Here, `yes' and `no' will be completed as the argument of options  whose  description  ends  in  a
              star;  file  names  will  be  completed  for  options  that  contain  the substring `=FILE' in the
              description; and directories will be completed for options whose description  contains  `=DIR'  or
              `=PATH'.   The last three are in fact the default and so need not be given explicitly, although it
              is possible to override the use of these patterns.  A typical help text which  uses  this  feature
              is:

                       -C, --directory=DIR          change to directory DIR

              so  that  the  above  specifications  will  cause directories to be completed after `--directory',
              though not after `-C'.

              Note also that _arguments tries to find out  automatically  if  the  argument  for  an  option  is
              optional.  This can be specified explicitly by doubling the colon before the message.

              If  the  pattern  ends in `(-)', this will be removed from the pattern and the action will be used
              only directly after the  `=',  not  in  the  next  word.   This  is  the  behaviour  of  a  normal
              specification defined with the form `=-'.

              By  default,  the  command  (with  the  option  `--help')  is  run  after resetting all the locale
              categories (except for LC_CTYPE) to `C'.  If the localized help  output  is  known  to  work,  the
              option  `-l'  can be specified after the `_arguments --' so that the command is run in the current
              locale.

              The `_arguments --' can be followed by the option `-i patterns' to give patterns for options which
              are not to be completed.  The patterns can be given as the name of an  array  parameter  or  as  a
              literal list in parentheses.  For example,

                     _arguments -- -i \
                         "(--(en|dis)able-FEATURE*)"

              will  cause  completion  to  ignore  the  options `--enable-FEATURE' and `--disable-FEATURE' (this
              example is useful with GNU configure).

              The `_arguments --' form can also be followed by the option `-s pair' to describe option  aliases.
              The  pair  consists  of a list of alternating patterns and corresponding replacements, enclosed in
              parens and quoted so that it forms a single argument word in the _arguments call.

              For example, some configure-script help output describes options only as `--enable-foo',  but  the
              script also accepts the negated form `--disable-foo'.  To allow completion of the second form:

                     _arguments -- -s "((#s)--enable- --disable-)"

              Miscellaneous notes

              Finally, note that _arguments generally expects to be the primary function handling any completion
              for which it is used.  It may have side effects which change the treatment of any matches added by
              other  functions  called  after  it.   To combine _arguments with other functions, those functions
              should be called either before _arguments, as  an  action  within  a  spec,  or  in  handlers  for
              `->state' actions.

              Here is a more general example of the use of _arguments:

                     _arguments '-l+:left border:' \
                                '-format:paper size:(letter A4)' \
                                '*-copy:output file:_files::resolution:(300 600)' \
                                ':postscript file:_files -g \*.\(ps\|eps\)' \
                                '*:page number:'

              This  describes  three  options:  `-l',  `-format',  and  `-copy'.   The  first takes one argument
              described as `left border' for which no completion will be offered because of  the  empty  action.
              Its argument may come directly after the `-l' or it may be given as the next word on the line.

              The `-format' option takes one argument in the next word, described as `paper size' for which only
              the strings `letter' and `A4' will be completed.

              The  `-copy'  option  may  appear more than once on the command line and takes two arguments.  The
              first is mandatory and will be completed as a filename.  The second is optional  (because  of  the
              second colon before the description `resolution') and will be completed from the strings `300' and
              `600'.

              The  last  two  descriptions  say  what should be completed as arguments.  The first describes the
              first argument as a `postscript file' and makes files ending in `ps' or `eps' be  completed.   The
              last  description  gives  all  other  arguments  the description `page numbers' but does not offer
              completions.

       _cache_invalid cache_identifier
              This function returns status zero if the  completions  cache  corresponding  to  the  given  cache
              identifier  needs  rebuilding.   It  determines  this by looking up the cache-policy style for the
              current context.  This should provide a function name which is run  with  the  full  path  to  the
              relevant cache file as the only argument.

              Example:

                     _example_caching_policy () {
                         # rebuild if cache is more than a week old
                         local -a oldp
                         oldp=( "$1"(Nm+7) )
                         (( $#oldp ))
                     }

       _call_function return name [ arg ... ]
              If  a  function  name exists, it is called with the arguments args.  The return argument gives the
              name of a parameter in which the return status from the function name should be stored; if  return
              is empty or a single hyphen it is ignored.

              The  return status of _call_function itself is zero if the function name exists and was called and
              non-zero otherwise.

       _call_program [ -l ] [ -p ] tag string ...
              This function provides a mechanism for the user to override the use of an  external  command.   It
              looks  up  the command style with the supplied tag.  If the style is set, its value is used as the
              command to execute.  The strings from the call to _call_program, or from the  style  if  set,  are
              concatenated with spaces between them and the resulting string is evaluated.  The return status is
              the return status of the command called.

              By  default,  the  command  is  run  in an environment where all the locale categories (except for
              LC_CTYPE) are reset to `C' by calling the utility function _comp_locale (see below). If the option
              `-l' is given, the command is run with the current locale.

              If the option `-p' is supplied  it  indicates  that  the  command  output  is  influenced  by  the
              permissions  it  is run with. If the gain-privileges style is set to true, _call_program will make
              use of commands such as sudo, if present on the command-line, to match the permissions to whatever
              the final command is likely to run under. When looking up the gain-privileges and command  styles,
              the  command  component  of the zstyle context will end with a slash (`/') followed by the command
              that would be used to gain privileges.

       _combination [ -s pattern ] tag style spec ... field opts ...
              This function is used to complete combinations of values,  for  example  pairs  of  hostnames  and
              usernames.   The  style  argument  gives  the  style which defines the pairs; it is looked up in a
              context with the tag specified.

              The style name consists of field names separated by hyphens, for example `users-hosts-ports'.  For
              each field for a value is already known, a  spec  of  the  form  `field=pattern'  is  given.   For
              example,  if  the  command  line  so  far  specifies a user `pws', the argument `users=pws' should
              appear.

              The next argument with no equals sign is taken as the name of  the  field  for  which  completions
              should be generated (presumably not one of the fields for which the value is known).

              The  matches  generated  will  be  taken  from  the  value of the style.  These should contain the
              possible values for the combinations in the appropriate order (users, hosts, ports in the  example
              above).   The  values  for the different fields are separated by colons.  This can be altered with
              the option -s to _combination which specifies a pattern.  Typically this is a character class,  as
              for   example  `-s  "[:@]"'  in  the  case  of  the  users-hosts  style.     Each  `field=pattern'
              specification restricts the completions which apply to elements of the  style  with  appropriately
              matching fields.

              If no style with the given name is defined for the given tag, or if none of the strings in style's
              value  match, but a function name of the required field preceded by an underscore is defined, that
              function will be called to generate the matches.  For example, if there is no  `users-hosts-ports'
              or  no  matching  hostname  when  a  host is required, the function `_hosts' will automatically be
              called.

              If the same name is used for more than one field, in both the  `field=pattern'  and  the  argument
              that  gives the name of the field to be completed, the number of the field (starting with one) may
              be given after the fieldname, separated from it by a colon.

              All arguments after the required field name are passed to compadd when generating matches from the
              style value, or to the functions for the fields if they are called.

       _command_names [ -e | - ]
              This function completes words that are valid at command  position:  names  of  aliases,  builtins,
              hashed commands, functions, and so on.  With the -e flag, only hashed commands are completed.  The
              - flag is ignored.

       _comp_locale
              This  function resets all the locale categories other than LC_CTYPE to `C' so that the output from
              external commands can be easily analyzed by the completion system. LC_CTYPE  retains  the  current
              value  (taking LC_ALL and LANG into account), ensuring that non-ASCII characters in file names are
              still handled properly.

              This function should normally be run only in a subshell, because the new locale is exported to the
              environment. Typical usage would be `$(_comp_locale; command ...)'.

       _completers [ -p ]
              This function completes names of completers.

              -p     Include the leading underscore (`_') in the matches.

       _describe [-12JVx] [ -oO | -t tag ] descr name1 [ name2 ] [ opt ... ]
                 [ -- name1 [ name2 ] [ opt ... ] ... ]
              This function associates completions with descriptions.  Multiple groups separated by  --  can  be
              supplied, potentially with different completion options opts.

              The  descr  is  taken  as  a  string  to  display  above  the  matches if the format style for the
              descriptions tag is set.  This is followed by one or two names of arrays followed  by  options  to
              pass to compadd.  The array name1 contains the possible completions with their descriptions in the
              form  `completion:description'.  Any literal colons in completion must be quoted with a backslash.
              If a name2 is given, it should have the same number  of  elements  as  name1;  in  this  case  the
              corresponding  elements  are  added as possible completions instead of the completion strings from
              name1.  The completion list will retain the descriptions from name1.  Finally, a set of completion
              options can appear.

              If the option `-o' appears before the first argument, the matches added will be treated  as  names
              of command options (N.B. not shell options), typically following a `-', `--' or `+' on the command
              line.  In this case _describe uses the prefix-hidden, prefix-needed and verbose styles to find out
              if  the  strings  should be added as completions and if the descriptions should be shown.  Without
              the `-o' option, only the verbose style is used to decide how descriptions are shown.  If `-O'  is
              used  instead  of  `-o',  command options are completed as above but _describe will not handle the
              prefix-needed style.

              With the -t option a tag can be specified.  The default is `values' or, if the -o option is given,
              `options'.

              The options -1, -2, -J, -V, -x are passed to _next_label.

              If selected by the list-grouped style, strings with the same description will appear  together  in
              the list.

              _describe  uses  the  _all_labels  function to generate the matches, so it does not need to appear
              inside a loop over tag labels.

       _description [ -x ] [ -12VJ ] tag name descr [ spec ... ]
              This function is not to be confused with the previous one; it is used as  a  helper  function  for
              creating  options  to  compadd.  It is buried inside many of the higher level completion functions
              and so often does not need to be called directly.

              The styles listed below are tested in the current context using  the  given  tag.   The  resulting
              options  for  compadd  are  put  into the array named name (this is traditionally `expl', but this
              convention is not enforced).  The description for the corresponding set of matches  is  passed  to
              the function in descr.

              The  styles  tested  are:  format,  hidden, matcher, ignore-line, ignored-patterns, group-name and
              sort.  The format style is first tested for the given tag and then for the descriptions tag if  no
              value was found, while the remainder are only tested for the tag given as the first argument.  The
              function also calls _setup which tests some more styles.

              The  string  returned  by  the format style (if any) will be modified so that the sequence `%d' is
              replaced by the descr given as the third argument without any leading  or  trailing  white  space.
              If,  after  removing  the white space, the descr is the empty string, the format style will not be
              used and the options put into the name  array  will  not  contain  an  explanation  string  to  be
              displayed above the matches.

              If  _description  is  called with more than three arguments, the additional specs should be of the
              form `char:str'.  These supply escape sequence replacements for the format style: every appearance
              of `%char' will be replaced by string.

              If the -x option is given, the description will be passed to compadd using the -x  option  instead
              of  the  default  -X.   This  means  that  the  description will be displayed even if there are no
              corresponding matches.

              The options placed in the array name take account of the group-name style, so matches  are  placed
              in  a  separate group where necessary.  The group normally has its elements sorted (by passing the
              option -J to compadd), but if an option starting with `-V', `-J',  `-1',  or  `-2'  is  passed  to
              _description,  that option will be included in the array.  Hence it is possible for the completion
              group to be unsorted by giving the option `-V', `-1V', or `-2V'.

              In most cases, the function will be used like this:

                     local expl
                     _description files expl file
                     compadd "$expl[@]" - "$files[@]"

              Note the use of the parameter expl, the hyphen, and the list of  matches.   Almost  all  calls  to
              compadd within the completion system use a similar format; this ensures that user-specified styles
              are correctly passed down to the builtins which implement the internals of completion.

       _dir_list [ -s sep ] [ -S ]
              Complete a list of directory names separated by colons (the same format as $PATH).

              -s sep Use sep as separator between items.  sep defaults to a colon (`:').

              -S     Add sep instead of slash (`/') as an autoremoveable suffix.

       _dispatch context string ...
              This sets the current context to context and looks for completion functions to handle this context
              by  hunting through the list of command names or special contexts (as described above for compdef)
              given as strings.  The first completion function to be defined for one of the contexts in the list
              is used to generate matches.  Typically, the last string is -default- to cause  the  function  for
              default completion to be used as a fallback.

              The  function  sets the parameter $service to the string being tried, and sets the context/command
              field (the fourth) of the $curcontext parameter to the context given as the first argument.

       _email_addresses [ -c ] [ -n plugin ]
              Complete email addresses.  Addresses are provided by plugins.

              -c     Complete bare localhost@domain.tld addresses, without a name part or  a  comment.   Without
                     this option, RFC822 `Firstname Lastname <address>' strings are completed.

              -n plugin
                     Complete aliases from plugin.

              The  following  plugins are available by default: _email-ldap (see the filter style), _email-local
              (completes  user@hostname  Unix  addresses),  _email-mail  (completes  aliases  from   ~/.mailrc),
              _email-mush, _email-mutt, and _email-pine.

              Addresses from the _email-foo plugin are added under the tag `email-foo'.

              Writing plugins

              Plugins  are  written  as separate functions with names starting with `_email-'.  They are invoked
              with the -c option and compadd options.  They should either do their own  completion  or  set  the
              $reply  array to a list of `alias:address' elements and return 300.  New plugins will be picked up
              and run automatically.

       _files The function _files is a wrapper around _path_files. It supports all of  the  same  functionality,
              with  some  enhancements -- notably, it respects the list-dirs-first style, and it allows users to
              override the behaviour of the -g and -/  options  with  the  file-patterns  style.  _files  should
              therefore be preferred over _path_files in most cases.

              This function accepts the full set of options allowed by _path_files, described below.

       _gnu_generic
              This  function is a simple wrapper around the _arguments function described above.  It can be used
              to determine automatically the long options understood by commands that produce a list when passed
              the option `--help'.  It is intended to be used as a top-level  completion  function  in  its  own
              right.  For example, to enable option completion for the commands foo and bar, use

                     compdef _gnu_generic foo bar

              after the call to compinit.

              The  completion  system  as  supplied  is  conservative  in  its use of this function, since it is
              important to be sure the command understands the option `--help'.

       _guard [ options ] pattern descr
              This function displays descr if pattern matches the string to be completed.  It is intended to  be
              used in the action for the specifications passed to _arguments and similar functions.

              The  return status is zero if the message was displayed and the word to complete is not empty, and
              non-zero otherwise.

              The pattern may be preceded by any of the options understood by compadd that are passed down  from
              _description,  namely  -M,  -J,  -V, -1, -2, -n, -F and -X.  All of these options will be ignored.
              This fits in conveniently with the argument-passing conventions of actions for _arguments.

              As an example, consider a command taking the options -n and -none, where -n must be followed by  a
              numeric value in the same word.  By using:

                     _arguments '-n-: :_guard "[0-9]#" "numeric value"' '-none'

              _arguments  can  be  made  to  both display the message `numeric value' and complete options after
              `-n<TAB>'.  If the `-n' is already followed by one or more digits (the pattern passed  to  _guard)
              only the message will be displayed; if the `-n' is followed by another character, only options are
              completed.

       _message [ -r12 ] [ -VJ group ] descr
       _message -e [ tag ] descr
              The  descr is used in the same way as the third argument to the _description function, except that
              the resulting string will always be shown whether or not matches were generated.  This  is  useful
              for displaying a help message in places where no completions can be generated.

              The format style is examined with the messages tag to find a message; the usual tag, descriptions,
              is used only if the style is not set with the former.

              If  the  -r  option  is  given,  no  style  is used; the descr is taken literally as the string to
              display.  This is most useful when the descr  comes  from  a  pre-processed  argument  list  which
              already contains an expanded description.  Note that this option does not disable the `%'-sequence
              parsing done by compadd.

              The  -12VJ  options  and the group are passed to compadd and hence determine the group the message
              string is added to.

              The second -e form gives a description for completions with the tag tag to be shown even if  there
              are  no  matches  for  that  tag.  This form is called by _arguments in the event that there is no
              action for an option specification.  The tag can be omitted and if so the tag is  taken  from  the
              parameter  $curtag;  this  is maintained by the completion system and so is usually correct.  Note
              that if there are no matches at the time this function is called, compstate[insert] is cleared, so
              additional matches generated later are not inserted on the command line.

       _multi_parts [ -i ] sep array
              The argument sep is a separator character.  The array may be either the name of an array parameter
              or a literal array in the form `(foo bar)', a parenthesised list of words separated by whitespace.
              The possible completions are the strings from the array.  However, each  chunk  delimited  by  sep
              will  be  completed separately.  For example, the _tar function uses `_multi_parts / patharray' to
              complete partial file paths from the given array of complete file paths.

              The -i option causes _multi_parts to  insert  a  unique  match  even  if  that  requires  multiple
              separators to be inserted.  This is not usually the expected behaviour with filenames, but certain
              other types of completion, for example those with a fixed set of possibilities, may be more suited
              to this form.

              Like  other utility functions, this function accepts the `-V', `-J', `-1', `-2', `-n', `-f', `-X',
              `-M', `-P', `-S', `-r', `-R', and `-q' options and passes them to the compadd builtin.

       _next_label [ -x ] [ -12VJ ] tag name descr [ option ... ]
              This function is used to implement the loop over different tag labels  for  a  particular  tag  as
              described  above for the tag-order style.  On each call it checks to see if there are any more tag
              labels; if there is it returns status zero, otherwise  non-zero.   As  this  function  requires  a
              current tag to be set, it must always follow a call to _tags or _requested.

              The  -x12VJ  options and the first three arguments are passed to the _description function.  Where
              appropriate the tag will be replaced by a tag label in this call.  Any description  given  in  the
              tag-order style is preferred to the descr passed to _next_label.

              The  options  given  after  the  descr are set in the parameter given by name, and hence are to be
              passed to compadd or whatever function is called to add the matches.

              Here is a typical use of this function for the tag foo.  The call to _requested determines if  tag
              foo  is  required  at all; the loop over _next_label handles any labels defined for the tag in the
              tag-order style.

                     local expl ret=1
                     ...
                     if _requested foo; then
                       ...
                       while _next_label foo expl '...'; do
                         compadd "$expl[@]" ... && ret=0
                       done
                       ...
                     fi
                     return ret

       _normal [ -P | -p precommand ]
              This is the standard function called to handle completion outside any special  -context-.   It  is
              called  both  to  complete  the  command word and also the arguments for a command.  In the second
              case, _normal looks for a special completion for that command, and if there is none  it  uses  the
              completion for the -default- context.

              A  second  use  is  to  reexamine  the command line specified by the $words array and the $CURRENT
              parameter after those have been modified.  For example, the function _precommand, which  completes
              after precommand specifiers such as nohup, removes the first word from the words array, decrements
              the  CURRENT  parameter,  then calls `_normal -p $service'.  The effect is that `nohup cmd ...' is
              treated in the same way as `cmd ...'.

              -P     Reset the list of precommands. This option should be used  if  completing  a  command  line
                     which   allows  internal  commands  (e.g.  builtins  and  functions)  regardless  of  prior
                     precommands (e.g. `zsh -c').

              -p precommand
                     Append precommand to the list of precommands. This option should  be  used  in  nearly  all
                     cases in which -P is not applicable.

              If  the  command name matches one of the patterns given by one of the options -p or -P to compdef,
              the corresponding completion function is called and then the parameter _compskip is  checked.   If
              it  is set completion is terminated at that point even if no matches have been found.  This is the
              same effect as in the -first- context.

       _options
              This can be used to complete the names of shell options.  It provides a matcher specification that
              ignores a leading  `no',  ignores  underscores  and  allows  upper-case  letters  to  match  their
              lower-case  counterparts  (for  example,  `glob',  `noglob',  `NO_GLOB'  are  all completed).  Any
              arguments are propagated to the compadd builtin.

       _options_set and _options_unset
              These functions complete only set or unset options, with the same matching specification  used  in
              the _options function.

              Note  that you need to uncomment a few lines in the _main_complete function for these functions to
              work properly.  The lines in question are used to store the option settings in effect  before  the
              completion widget locally sets the options it needs.  Hence these functions are not generally used
              by the completion system.

       _parameters
              This is used to complete the names of shell parameters.

              The  option  `-g pattern' limits the completion to parameters whose type matches the pattern.  The
              type of a parameter is that shown by `print ${(t)param}', hence judicious use of `*' in pattern is
              probably necessary.

              All other arguments are passed to the compadd builtin.

       _path_files
              This function is  used  throughout  the  completion  system  to  complete  filenames.   It  allows
              completion  of  partial  paths.   For  example,  the  string  `/u/i/s/sig'  may  be  completed  to
              `/usr/include/sys/signal.h'.

              The options accepted by both _path_files and _files are:

              -f     Complete all filenames.  This is the default.

              -/     Specifies that only directories should be completed.

              -g pattern
                     Specifies that only files matching the pattern should be completed.

              -W paths
                     Specifies path prefixes that are to be prepended to the string from  the  command  line  to
                     generate  the  filenames  but  that  should  not  be  inserted  as completions nor shown in
                     completion listings.  Here, paths may be the name of an array parameter, a literal list  of
                     paths enclosed in parentheses or an absolute pathname.

              -F ignored-files
                     This  behaves  as  for  the  corresponding  option to the compadd builtin.  It gives direct
                     control over which filenames should  be  ignored.   If  the  option  is  not  present,  the
                     ignored-patterns style is used.

              Both  _path_files  and _files also accept the following options which are passed to compadd: `-J',
              `-V', `-1', `-2', `-n', `-X', `-M', `-P', `-S', `-q', `-r', and `-R'.

              Finally, the _path_files function  uses the styles expand, ambiguous, special-dirs,  list-suffixes
              and file-sort described above.

       _pick_variant [ -b builtin-label ] [ -c command ] [ -r name ]
                     label=pattern ... label [ arg ... ]
              This  function  is  used  to resolve situations where a single command name requires more than one
              type of handling, either because it has more than one variant or because there  is  a  name  clash
              between two different commands.

              The command to run is taken from the first element of the array words unless this is overridden by
              the  option  -c.   This  command  is  run  and  its  output is compared with a series of patterns.
              Arguments to be passed to the command can be specified at the end after all the  other  arguments.
              The  patterns  to try in order are given by the arguments label=pattern; if the output of `command
              arg ...' contains pattern, then label is selected as the label for the command variant.   If  none
              of the patterns match, the final command label is selected and status 1 is returned.

              If  the  `-b  builtin-label'  is  given, the command is tested to see if it is provided as a shell
              builtin, possibly autoloaded; if so, the label builtin-label is selected  as  the  label  for  the
              variant.

              If the `-r name' is given, the label picked is stored in the parameter named name.

              The  results  are  also  cached  in  the _cmd_variant associative array indexed by the name of the
              command run.

       _regex_arguments name spec ...
              This function generates a completion function name which matches the specifications specs,  a  set
              of  regular  expressions  as  described  below.  After running _regex_arguments, the function name
              should be called as a normal completion function.  The pattern to  be  matched  is  given  by  the
              contents  of  the  words  array  up  to  the  current  cursor  position  joined together with null
              characters; no quotation is applied.

              The arguments are grouped as sets of alternatives separated by `|', which are tried one after  the
              other  until  one  matches.   Each  alternative consists of a one or more specifications which are
              tried left to right, with each pattern matched being stripped in turn from the command line  being
              tested,  until  all  of  the  group  succeeds  or  until  one  fails; in the latter case, the next
              alternative is tried.  This structure can be repeated to arbitrary  depth  by  using  parentheses;
              matching proceeds from inside to outside.

              A  special procedure is applied if no test succeeds but the remaining command line string contains
              no null character (implying the remaining word  is  the  one  for  which  completions  are  to  be
              generated).   The  completion  target  is restricted to the remaining word and any actions for the
              corresponding patterns are executed.  In this case, nothing is  stripped  from  the  command  line
              string.   The  order  of  evaluation  of the actions can be determined by the tag-order style; the
              various formats supported by _alternative can be used in action.  The descr is used for setting up
              the array parameter expl.

              Specification arguments take one of following forms, in which metacharacters such as `(', `)', `#'
              and `|' should be quoted.

              /pattern/ [%lookahead%] [-guard] [:tag:descr:action]
                     This is a single primitive component.  The function  tests  whether  the  combined  pattern
                     `(#b)((#B)pattern)lookahead*' matches the command line string.  If so, `guard' is evaluated
                     and  its  return  status  is  examined to determine if the test has succeeded.  The pattern
                     string `[]' is guaranteed never to match.  The lookahead is not stripped from  the  command
                     line before the next pattern is examined.

                     The argument starting with : is used in the same manner as an argument to _alternative.

                     A component is used as follows: pattern is tested to see if the component already exists on
                     the  command line.  If it does, any following specifications are examined to find something
                     to complete.  If a component is reached but no such pattern exists yet on the command line,
                     the string containing the action is used to generate matches to insert at that point.

              /pattern/+ [%lookahead%] [-guard] [:tag:descr:action]
                     This is similar to `/pattern/ ...' but the left part of the command line string  (i.e.  the
                     part  already  matched  by  previous  patterns)  is  also considered part of the completion
                     target.

              /pattern/- [%lookahead%] [-guard] [:tag:descr:action]
                     This is similar to `/pattern/ ...' but the actions of the current  and  previously  matched
                     patterns are ignored even if the following `pattern' matches the empty string.

              ( spec )
                     Parentheses  may  be  used  to  groups specs; note each parenthesis is a single argument to
                     _regex_arguments.

              spec # This allows any number of repetitions of spec.

              spec spec
                     The two specs are to be matched one after the other as described above.

              spec | spec
                     Either of the two specs can be matched.

              The function _regex_words can be used as a helper function  to  generate  matches  for  a  set  of
              alternative words possibly with their own arguments as a command line argument.

              Examples:

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                         /$'[^\0]#\0'/ :'compadd aaa'

              This  generates  a function _tst that completes aaa as its only argument.  The tag and description
              for the action have been omitted for brevity (this works but is not recommended  in  normal  use).
              The  first  component  matches  the  command  word,  which  is  arbitrary; the second matches  any
              argument.  As the argument is also arbitrary, any following component  would  not  depend  on  aaa
              being present.

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                         /$'aaa\0'/ :'compadd aaa'

              This  is a more typical use; it is similar, but any following patterns would only match if aaa was
              present as the first argument.

                     _regex_arguments _tst /$'[^\0]#\0'/ \( \
                         /$'aaa\0'/ :'compadd aaa' \
                         /$'bbb\0'/ :'compadd bbb' \) \#

              In this example, an indefinite number of command arguments may be completed.   Odd  arguments  are
              completed  as  aaa  and  even  arguments  as  bbb.  Completion fails unless the set of aaa and bbb
              arguments before the current one is matched correctly.

                     _regex_arguments _tst /$'[^\0]#\0'/ \
                         \( /$'aaa\0'/ :'compadd aaa' \| \
                         /$'bbb\0'/ :'compadd bbb' \) \#

              This is similar, but either aaa  or  bbb  may  be  completed  for  any  argument.   In  this  case
              _regex_words could be used to generate a suitable expression for the arguments.

       _regex_words tag description spec ...
              This  function  can  be  used  to generate arguments for the _regex_arguments command which may be
              inserted at any point where a set of rules is expected.  The tag and description give  a  standard
              tag  and description pertaining to the current context.  Each spec contains two or three arguments
              separated by a colon: note that there is no leading colon in this case.

              Each spec gives one of a set of  words  that  may  be  completed  at  this  point,  together  with
              arguments.   It  is  thus  roughly  equivalent  to  the  _arguments  function  when used in normal
              (non-regex) completion.

              The part of the spec before the first colon is the word to be completed.  This may  contain  a  *;
              the  entire  word, before and after the * is completed, but only the text before the * is required
              for the context to be matched, so that further arguments may be completed  after  the  abbreviated
              form.

              The second part of spec is a description for the word being completed.

              The  optional  third  part  of  the spec describes how words following the one being completed are
              themselves to be completed.  It will be evaluated in order to avoid problems with  quoting.   This
              means  that  typically  it  contains a reference to an array containing previously generated regex
              arguments.

              The option -t term specifies a terminator for the word  instead  of  the  usual  space.   This  is
              handled as an auto-removable suffix in the manner of the option -s sep to _values.

              The  result  of  the processing by _regex_words is placed in the array reply, which should be made
              local to the calling function.  If the set of words and arguments may be matched repeatedly,  a  #
              should be appended to the generated array at that point.

              For example:

                     local -a reply
                     _regex_words mydb-commands 'mydb commands' \
                       'add:add an entry to mydb:$mydb_add_cmds' \
                       'show:show entries in mydb'
                     _regex_arguments _mydb "$reply[@]"
                     _mydb "$@"

              This  shows  a  completion  function for a command mydb which takes two command arguments, add and
              show.  show takes no arguments, while the arguments for add have already been prepared in an array
              mydb_add_cmds, quite possibly by a previous call to _regex_words.

       _requested [ -x ] [ -12VJ ] tag [ name descr [ command [ arg ... ] ]
              This function is called to decide whether a tag already registered by a call to _tags (see  below)
              has been requested by the user and hence completion should be performed for it.  It returns status
              zero  if the tag is requested and non-zero otherwise.  The function is typically used as part of a
              loop over different tags as follows:

                     _tags foo bar baz
                     while _tags; do
                       if _requested foo; then
                         ... # perform completion for foo
                       fi
                       ... # test the tags bar and baz in the same way
                       ... # exit loop if matches were generated
                     done

              Note that the test for whether matches were generated is not performed until the end of the  _tags
              loop.   This  is  so  that  the  user  can  set the tag-order style to specify a set of tags to be
              completed at the same time.

              If name and descr are given, _requested calls  the  _description  function  with  these  arguments
              together with the options passed to _requested.

              If  command is given, the _all_labels function will be called immediately with the same arguments.
              In simple cases this makes it possible to perform the test for the tag and the matching in one go.
              For example:

                     local expl ret=1
                     _tags foo bar baz
                     while _tags; do
                       _requested foo expl 'description' \
                           compadd foobar foobaz && ret=0
                       ...
                       (( ret )) || break
                     done

              If the command is not compadd, it must nevertheless be prepared to handle the same options.

       _retrieve_cache cache_identifier
              This function retrieves completion information from the file given by cache_identifier, stored  in
              a  directory specified by the cache-path style which defaults to ~/.zcompcache.  The return status
              is zero if retrieval was successful.  It will only attempt retrieval if  the  use-cache  style  is
              set,  so  you  can  call  this  function without worrying about whether the user wanted to use the
              caching layer.

              See _store_cache below for more details.

       _sep_parts
              This function is passed alternating arrays  and  separators  as  arguments.   The  arrays  specify
              completions  for  parts of strings to be separated by the separators.  The arrays may be the names
              of array parameters or a quoted list of  words  in  parentheses.   For  example,  with  the  array
              `hosts=(ftp  news)'  the  call  `_sep_parts  '(foo bar)' @ hosts' will complete the string  `f' to
              `foo' and the string `b@n' to `bar@news'.

              This function accepts the compadd options `-V', `-J', `-1', `-2', `-n', `-X',  `-M',  `-P',  `-S',
              `-r', `-R', and `-q' and passes them on to the compadd builtin used to add the matches.

       _sequence [ -s sep ] [ -n max ] [ -d ] function [ - ] ...
              This  function  is a wrapper to other functions for completing items in a separated list. The same
              function is used to complete each item in the list. The separator is specified with the -s option.
              If -s is omitted it will use `,'. Duplicate values are not matched  unless  -d  is  specified.  If
              there is a fixed or maximum number of items in the list, this can be specified with the -n option.

              Common  compadd options are passed on to the function. It is possible to use compadd directly with
              _sequence, though _values may be more appropriate in this situation.

       _setup tag [ group ]
              This function sets up the special parameters used by the completion system appropriately  for  the
              tag  given  as  the first argument.  It uses the styles list-colors, list-packed, list-rows-first,
              last-prompt, accept-exact, menu and force-list.

              The optional group supplies the name of the group in which the matches will be placed.  If  it  is
              not given, the tag is used as the group name.

              This  function  is  called  automatically  from  _description  and  hence  is  not normally called
              explicitly.

       _store_cache cache_identifier param ...
              This function, together with _retrieve_cache and _cache_invalid, implements a caching layer  which
              can  be  used  in  any  completion  function.   Data  obtained  by costly operations are stored in
              parameters; this function then dumps the values of those parameters to a file.  The data can  then
              be retrieved quickly from that file via _retrieve_cache, even in different instances of the shell.

              The cache_identifier specifies the file which the data should be dumped to.  The file is stored in
              a  directory  specified  by  the  cache-path style which defaults to ~/.zcompcache.  The remaining
              params arguments are the parameters to dump to the file.

              The return status is zero if storage was successful.  The function will only  attempt  storage  if
              the  use-cache style is set, so you can call this function without worrying about whether the user
              wanted to use the caching layer.

              The completion function may avoid calling _retrieve_cache when it already has the completion  data
              available as parameters.  However, in that case it should call _cache_invalid to check whether the
              data in the parameters and in the cache are still valid.

              See the _perl_modules completion function for a simple example of the usage of the caching layer.

       _tags [ [ -C name ] tag ... ]
              If  called  with  arguments,  these are taken to be the names of tags valid for completions in the
              current context.  These tags are stored internally and sorted by using the tag-order style.

              Next, _tags is called repeatedly without  arguments  from  the  same  completion  function.   This
              successively selects the first, second, etc. set of tags requested by the user.  The return status
              is  zero if at least one of the tags is requested and non-zero otherwise.  To test if a particular
              tag is to be tried, the _requested function should be called (see above).

              If `-C name' is given, name is temporarily stored in the argument field (the fifth) of the context
              in the curcontext parameter during the call to _tags; the field is restored on exit.  This  allows
              _tags  to  use a more specific context without having to change and reset the curcontext parameter
              (which has the same effect).

       _tilde_files
              Like _files, but resolve leading tildes according to the  rules  of  filename  expansion,  so  the
              suggested completions don't start with a `~' even if the filename on the command-line does.

       _values [ -O name ] [ -s sep ] [ -S sep ] [ -wC ] desc spec ...
              This  is  used  to  complete  arbitrary  keywords  (values)  and their arguments, or lists of such
              combinations.

              If the first argument is the option `-O name', it  will  be  used  in  the  same  way  as  by  the
              _arguments  function.   In  other  words, the elements of the name array will be passed to compadd
              when executing an action.

              If the first argument (or the first argument after `-O name') is `-s', the next argument  is  used
              as the character that separates multiple values.  This character is automatically added after each
              value in an auto-removable fashion (see below); all values completed by `_values -s' appear in the
              same word on the command line, unlike completion using _arguments.  If this option is not present,
              only a single value will be completed per word.

              Normally,  _values will only use the current word to determine which values are already present on
              the command line and hence are not to be completed again.   If  the  -w  option  is  given,  other
              arguments are examined as well.

              The  first non-option argument, desc, is used as a string to print as a description before listing
              the values.

              All other arguments describe the possible values and their arguments in the same format  used  for
              the  description of options by the _arguments function (see above).  The only differences are that
              no minus or plus sign is required at the beginning, values can have only  one  argument,  and  the
              forms of action beginning with an equal sign are not supported.

              The  character  separating  a  value  from  its  argument can be set using the option -S (like -s,
              followed by the character to use as the separator in the next argument).  By  default  the  equals
              sign will be used as the separator between values and arguments.

              Example:

                     _values -s , 'description' \
                             '*foo[bar]' \
                             '(two)*one[number]:first count:' \
                             'two[another number]::second count:(1 2 3)'

              This  describes  three possible values: `foo', `one', and `two'.  The first is described as `bar',
              takes no argument and may appear more than once.  The second is described as `number', may  appear
              more  than  once,  and  takes  one  mandatory  argument  described  as `first count'; no action is
              specified, so it will not be completed.  The `(two)' at the beginning says that if the value `one'
              is on the line, the value `two' will no longer be considered a possible completion.  Finally,  the
              last  value  (`two')  is described as `another number' and takes an optional argument described as
              `second count' for which the completions (to appear after an `=') are  `1',  `2',  and  `3'.   The
              _values function will complete lists of these values separated by commas.

              Like  _arguments,  this  function temporarily adds another context name component to the arguments
              element (the fifth) of the current context while executing the action.  Here this name is just the
              name of the value for which the argument is completed.

              The style verbose is used to decide if the descriptions for the values  (but  not  those  for  the
              arguments) should be printed.

              The  associative array val_args is used to report values and their arguments; this works similarly
              to the opt_args associative array used by _arguments.  Hence the function calling  _values  should
              declare the local parameters state, state_descr, line, context and val_args:

                     local context state state_descr line
                     typeset -A val_args

              when using an action of the form `->string'.  With this function the context parameter will be set
              to  the name of the value whose argument is to be completed.  Note that for _values, the state and
              state_descr are scalars rather than arrays.  Only a single matching state is returned.

              Note also that _values normally adds the character used as the  separator  between  values  as  an
              auto-removable  suffix  (similar to a `/' after a directory).  However, this is not possible for a
              `->string' action as the matches for the argument are generated by the calling function.   To  get
              the  usual  behaviour,  the  calling  function  can add the separator x as a suffix by passing the
              options `-qS x' either directly or indirectly to compadd.

              The option -C is treated in the same way as it is by  _arguments.   In  that  case  the  parameter
              curcontext should be made local instead of context (as described above).

       _wanted [ -x ] [ -C name ]  [ -12VJ ] tag name descr command [ arg ...]
              In   many  contexts,  completion  can  only  generate  one  particular  set  of  matches,  usually
              corresponding to a single tag.  However, it is still necessary to decide whether the user requires
              matches of this type.  This function is useful in such a case.

              The arguments to _wanted are the same as those to _requested,  i.e.  arguments  to  be  passed  to
              _description.   However,  in  this  case the command is not optional;  all the processing of tags,
              including the loop over both tags and tag labels and the generation of  matches,  is  carried  out
              automatically by _wanted.

              Hence  to  offer  only  one  tag  and  immediately  add  the  corresponding matches with the given
              description:

                     local expl
                     _wanted tag expl 'description' \
                         compadd matches...

              Note that, as for _requested, the command must be able to accept options  to  be  passed  down  to
              compadd.

              Like  _tags this function supports the -C option to give a different name for the argument context
              field.  The -x option has the same meaning as for _description.

       _widgets [ -g pattern ]
              This function completes names of zle widgets  (see  the  section  `Widgets'  in  zshzle(1)).   The
              pattern,  if  present,  is matched against values of the $widgets special parameter, documented in
              the section `The zsh/zleparameter Module' in zshmodules(1).

COMPLETION SYSTEM VARIABLES

       There are some standard variables, initialised by the _main_complete function and then  used  from  other
       functions.

       The standard variables are:

       _comp_caller_options
              The  completion system uses setopt to set a number of options. This allows functions to be written
              without concern for compatibility with  every  possible  combination  of  user  options.  However,
              sometimes  completion needs to know what the user's option preferences are. These are saved in the
              _comp_caller_options associative array. Option names, spelled in  lowercase  without  underscores,
              are mapped to one or other of the strings `on' and `off'.

              _comp_priv_prefix
                     Completion  functions such as _sudo can set the _comp_priv_prefix array to a command prefix
                     that may then be used by _call_program to match the privileges  when  calling  programs  to
                     generate matches.

              Two  more  features  are  offered  by  the  _main_complete  function.  The arrays compprefuncs and
              comppostfuncs may contain names of functions that are to be called  immediately  before  or  after
              completion  has  been  tried.   A function will only be called once unless it explicitly reinserts
              itself into the array.

COMPLETION DIRECTORIES

       In the source distribution,  the  files  are  contained  in  various  subdirectories  of  the  Completion
       directory.   They  may  have been installed in the same structure, or into one single function directory.
       The following is a description of the files found in the original directory structure.  If  you  wish  to
       alter  an  installed file, you will need to copy it to some directory which appears earlier in your fpath
       than the standard directory where it appears.

       Base   The core functions and special completion widgets automatically bound to keys.  You will certainly
              need most of these, though will probably not need to alter them.  Many  of  these  are  documented
              above.

       Zsh    Functions for completing arguments of shell builtin commands and utility functions for this.  Some
              of these are also used by functions from the Unix directory.

       Unix   Functions  for  completing  arguments  of external commands and suites of commands.  They may need
              modifying for your system, although in many cases some attempt is made to decide which version  of
              a command is present.  For example, completion for the mount command tries to determine the system
              it  is running on, while completion for many other utilities try to decide whether the GNU version
              of the command is in use, and hence whether the --help option is supported.

       X, AIX, BSD, ...
              Completion and utility function for commands available  only  on  some  systems.   These  are  not
              arranged  hierarchically, so, for example, both the Linux and Debian directories, as well as the X
              directory, may be useful on your system.

zsh 5.8.1                                       February 12, 2022                                  ZSHCOMPSYS(1)