Ubuntu Manpage: UIL — The user interface language file format "user interface language" "UIL"

NAME

       UIL — The user interface language file format "user interface language" "UIL"

SYNOPSIS

       MODULE module_name
       [ NAMES = CASE_INSENSITIVE | CASE_SENSITIVE ]
       [ CHARACTER_SET = character_set ]
       [ OBJECTS = { widget_name = GADGET | WIDGET; [...] } ]
       { [
       [ value_section ] |
       [ procedure_section ] |
       [ list_section ] |
       [ object_section ] |
       [ identifier_section ]
       [ ... ]
       ] }
       END MODULE;

DESCRIPTION

The UIL language is used for describing the initial state of a user interface for a widget based
application. UIL describes the widgets used in the interface, the resources of those widgets, and the
callbacks of those widgets. The UIL file is compiled into a UID file using the command uil or by the
callable compiler Uil(). The contents of the compiled UID file can then be accessed by the various Motif
Resource Management (MRM) functions from within an application program.

The UID file is independent of the platform on which the Motif program will eventually be run. In other
words, the same UID file can be used on any system that can run Motif.

File
A UIL file consists of a single complete module, described in the syntax description above, or, if the
file is to be included in a larger UIL file, one complete "section," as described below. UIL uses five
different kinds of sections: value, procedure, list, object, and identifier.

UIL is a free-form language. This means that high-level constructs such as object and value declarations
do not need to begin in any particular column and can span any number of lines. Low-level constructs such
as keywords and punctuation characters can also begin in any column; however, except for string literals
and comments, they cannot span lines.

The UIL compiler accepts input lines up to 132 characters in length.

MODULE module_name
The name by which the UIL module is known in the UID file. This name is stored in the UID file
for later use in the retrieval of resources by the MRM. This name is always stored in
uppercase in the UID file.

NAMES = CASE_INSENSITIVE | CASE_SENSITIVE
"UIL" "case sensitivity clause"

Indicates whether names should be treated as case sensitive or case insensitive. The default is
case sensitive. The case-sensitivity clause should be the first clause in the module header,
and in any case must precede any statement that contains a name. If names are case sensitive
in a UIL module, UIL keywords in that module must be in lowercase. Each name is stored in the
UIL file in the same case as it appears in the UIL module. If names are case insensitive, then
keywords can be in uppercase, lowercase, or mixed case, and the uppercase equivalent of each
name is stored in the UID file.

CHARACTER_SET = character_set
"UIL" "default character set clause"

Specifies the default character set for string literals in the module that do not explicitly
set their character set. The default character set, in the absence of this clause is the
codeset component of the LANG environment variable, or the value of XmFALLBACK_CHARSET if LANG
is not set or has no codeset component. The value of XmFALLBACK_CHARSET is defined by the UIL
supplier, but is usually ISO8859-1 (equivalent to ISO_LATIN1). Use of this clause turns off
all localized string literal processing turned on by the compiler flag -s or the
Uil_command_type data structure element use_setlocale_flag.

OBJECTS = { widget_name = GADGET | WIDGET; }
"UIL" "objects clause"

Indicates whether the widget or gadget form of the control specified by widget_name is used by
default. By default the widget form is used, so the gadget keyword is usually the only one
used. The specified control should be one that has both a widget and gadget version:
XmCascadeButton, XmLabel, XmPushButton, XmSeparator, and XmToggleButton. The form of more than
one control can be specified by delimiting them with semicolons. The gadget or widget form of
an instance of a control can be specified with the GADGET and WIDGET keywords in a particular
object declaration.

value_section
Provides a way to name a value expression or literal. The value name can then be referred to
by declarations that occur elsewhere in the UIL module in any context where a value can be
used. Values can be forward referenced. Value sections are described in more detail later in
the reference page.

procedure_section
Defines the callback routines used by a widget and the creation routines for user-defined
widgets. These definitions are used for error checking. Procedure sections are described in
more detail later in the reference page.

list_section
Provides a way to group together a set of arguments, controls (children), callbacks, or
procedures for later use in the UIL module. Lists can contain other lists, so that you can set
up a hierarchy to clearly show which arguments, controls, callbacks, and procedures are common
to which widgets. List sections are described in more detail later in the reference page.

object_section
Defines the objects that make up the user interface of the application. You can reference the
object names in declarations that occur elsewhere in the UIL module in any context where an
object name can be used (for example, in a controls list, as a symbolic reference to a widget
ID, or as the tag_value argument for a callback procedure). Objects can be forward referenced.
Object sections are described in more detail later in the reference page.

identifier_section
Defines a run-time binding of data to names that appear in the UIL module. Identifier sections
are described in more detail later in the reference page.

The UIL file can also contain comments and include directives, which are described along with the main
elements of the UIL file format in the following sections.

Comments
Comments can take one of two forms, as follows:

• The comment is introduced with the sequence /* followed by the text of the comment and terminated
with the sequence */. This form of comment can span multiple source lines.

• The comment is introduced with an ! (exclamation point), followed by the text of the comment and
terminated by the end of the source line.

Neither form of comment can be nested.

Value sections
"UIL" "value section" A value section consists of the keyword VALUE followed by a sequence of value
declarations. It has the following syntax:

VALUE value_name : [ EXPORTED | PRIVATE ] value_expression | IMPORTED value_type ;

Where value_expression is assigned to value_name or a value_type is assigned to an imported value name.
A value declaration provides a way to name a value expression or literal. The value name can be referred
to by declarations that occur later in the UIL module in any context where a value can be used. Values
can be forward referenced. "IMPORTED" "EXPORTED" "PRIVATE"

EXPORTED A value that you define as exported is stored in the UID file as a named resource, and
therefore can be referenced by name in other UID files. When you define a value as exported,
MRM looks outside the module in which the exported value is declared to get its value at run
time.

PRIVATE A private value is a value that is not imported or exported. A value that you define as
private is not stored as a distinct resource in the UID file. You can reference a private
value only in the UIL module containing the value declaration. The value or object is directly
incorporated into anything in the UIL module that references the declaration.

IMPORTED A value that you define as imported is one that is defined as a named resource in a UID file.
MRM resolves this declaration with the corresponding exported declaration at application run
time.

By default, values and objects are private. The following is a list of the supported value types in UIL:

• ANY

• ARGUMENT

• BOOLEAN

• COLOR

• COLOR_TABLE

• COMPOUND_STRING

• FLOAT

• FONT

• FONT_TABLE

• FONTSET

• ICON

• INTEGER

• INTEGER_TABLE

• KEYSYM

• REASON

• SINGLE_FLOAT

• STRING

• STRING_TABLE

• TRANSLATION_TABLE

• WIDE_CHARACTER

• WIDGET

Procedure sections
"UIL" "procedure section" A procedure section consists of the keyword PROCEDURE followed by a sequence of
procedure declarations. It has the following syntax:

PROCEDURE
procedure_name [ ( [ value_type ]) ];

"UIL" "procedure declaration" Use a procedure declaration to declare

• A routine that can be used as a callback routine for a widget

• The creation function for a user-defined widget

You can reference a procedure name in declarations that occur later in the UIL module in any context
where a procedure can be used. Procedures can be forward referenced. You cannot use a name you used in
another context as a procedure name.

In a procedure declaration, you have the option of specifying that a parameter will be passed to the
corresponding callback routine at run time. This parameter is called the callback tag. You can specify
the data type of the callback tag by putting the data type in parentheses following the procedure name.
When you compile the module, the UIL compiler checks that the argument you specify in references to the
procedure is of this type. Note that the data type of the callback tag must be one of the valid UIL data
types. You can use a widget as a callback tag, as long as the widget is defined in the same widget
hierarchy as the callback, that is they have a common ancestor that is in the same UIL hierarchy.

The following list summarizes how the UIL compiler checks argument type and argument count, depending on
the procedure declaration.

No parameters
No argument type or argument count checking occurs. You can supply either 0 or one arguments
in the procedure reference.

( ) Checks that the argument count is 0 (zero).

(ANY) Checks that the argument count is 1. Does not check the argument type. Use the ANY type to
prevent type checking on procedure tags.

(type) Checks for one argument of the specified type.

(class_name)
Checks for one widget argument of the specified widget class.

While it is possible to use any UIL data type to specify the type of a tag in a procedure declaration,
you must be able to represent that data type in the programming language you are using. Some data types
(such as integer, Boolean, and string) are common data types recognized by most programming languages.
Other UIL data types (such as string tables) are more complicated and may require that you set up an
appropriate corresponding data structure in the application in order to pass a tag of that type to a
callback routine.

You can also use a procedure declaration to specify the creation function for a user-defined widget. In
this case, you specify no formal parameters. The procedure is invoked with the standard three arguments
passed to all widget creation functions. (See the Motif Toolkit documentation for more information about
widget creation functions.)

List sections
"UIL" "list section" A list section consists of the keyword LIST followed by a sequence of list
declarations. It has the following syntax:

LIST
list_name: { list_item; [...] }
[...]

You can also use list sections to group together a set of arguments, controls (children), callbacks, or
procedures for later use in the UIL module. Lists can contain other lists, so that you can set up a
hierarchy to clearly show which arguments, controls, callbacks, and procedures are common to which
widgets. You cannot mix the different types of lists; a list of a particular type cannot contain entries
of a different list type or reference the name of a different list type. A list name is always private
to the UIL module in which you declare the list and cannot be stored as a named resource in a UID file.

The additional list types are described in the following sections.

Arguments List Structure

"List types" "argument" "UIL" "arguments list" An arguments list defines which arguments are to be
specified in the arguments list parameter when the creation routine for a particular object is called at
run time. An arguments list also specifies the values for those arguments. Argument lists have the
following syntax:

LIST
list_name: ARGUMENTS {
argument_name = value_expression;
[...] }
[...]

The argument name must be either a built-in argument name or a user-defined argument name that is
specified with the ARGUMENT function.

If you use a built-in argument name as an arguments list entry in an object definition, the UIL compiler
checks the argument name to be sure that it is supported by the type of object that you are defining. If
the same argument name appears more than once in a given arguments list, the last entry that uses that
argument name supersedes all previous entries with that name, and the compiler issues a message.

Some arguments, such as XmNitems and XmNitemCount, are coupled by the UIL compiler. When you specify one
of the arguments, the compiler also sets the other. The coupled argument is not available to you. "UIL"
"coupled arguments" "Arguments" "coupled in UIL"

The Motif Toolkit and the X Toolkit (intrinsics) support constraint arguments. A constraint argument is
one that is passed to children of an object, beyond those arguments normally available. For example, the
Form widget grants a set of constraint arguments to its children. These arguments control the position
of the children within the Form.

Unlike the arguments used to define the attributes of a particular widget, constraint arguments are used
exclusively to define additional attributes of the children of a particular widget. These attributes
affect the behavior of the children within their parent. To supply constraint arguments to the children,
you include the arguments in the arguments list for the child.

See Appendix B for information about which arguments are supported by which widgets. See Appendix C for
information about what the valid value type is for each built-in argument.

Callbacks List Structure "UIL" "callbacks list" "List types" "callback"

Use a callbacks list to define which callback reasons are to be processed by a particular widget at run
time. Callback lists have the following syntax:

LIST list_name : CALLBACKS { reason_name = PROCEDURE procedure_name [ ( [ value_expression ] ) ]; |
reason_name = procedure_list ; [...] } [...]

For Motif Toolkit widgets, the reason name must be a built-in reason name. For a user-defined widget, you
can use a reason name that you previously specified using the REASON function. If you use a built-in
reason in an object definition, the UIL compiler ensures that reason is supported by the type of object
you are defining. Appendix B shows which reasons each object supports.

If the same reason appears more than once in a callbacks list, the last entry referring to that name
supersedes all previous entries using the same reason, and the UIL compiler issues a diagnostic message.

If you specify a named value for the procedure argument (callback tag), the data type of the value must
match the type specified for the callback tag in the corresponding procedure declaration. When
specifying a widget name as a procedure value expression you must also specify the type of the widget and
a space before the name of the widget.

Because the UIL compiler produces a UID file rather than an object module (.o), the binding of the UIL
name to the address of the entry point to the procedure is not done by the loader, but is established at
run time with the MRM function MrmRegisterNames. You call this function before fetching any objects,
giving it both the UIL names and the procedure addresses of each callback. The name you register with MRM
in the application program must match the name you specified for the procedure in the UIL module.

Each callback procedure receives three arguments. The first two arguments have the same form for each
callback. The form of the third argument varies from object to object.

The first argument is the address of the data structure maintained by the Motif Toolkit for this object
instance. This address is called the widget ID for this object.

The second argument is the address of the value you specified in the callbacks list for this procedure.
If you do not specify an argument, the address is NULL. Note that, in the case where the value you
specified is a string or an XmString, the value specified in the callbacks list already represents an
address rather than an actual value. In the case of a simple string, for example, the value is the
address of the first character of that string. In these cases, UIL does not add a level of indirection,
and the second argument to the callback procedure is simply the value as specified in the callbacks list.

The third argument is the reason name you specified in the callbacks list.

Controls List Structure

"UIL" "controls list" A controls list defines which objects are children of, or controlled by, a
particular object. Each entry in a controls list has the following syntax:

LIST
list_name: CONTROLS {
[child_name: ] [MANAGED | UNMANAGED] object_definition;
[...] }
[...]

If you specify the keyword MANAGED at run time, the object is created and managed; if you specify
UNMANAGED at run time, the object is only created. Objects are managed by default.

You can use child_name to specify resources for the automatically created children of a particular
control. Names for automatically created children are formed by appending Xm_ to the name of the child
widget. This name is specified in the documentation for the parent widget.

Unlike the arguments list and the callbacks list, a controls list entry that is identical to a previous
entry does not supersede the previous entry. At run time, each controls list entry causes a child to be
created when the parent is created. If the same object definition is used for multiple children, multiple
instances of the child are created at run time. See Appendix B for a list of which widget types can be
controlled by which other widget types.

Procedures List Structure

You can specify multiple procedures for a callback reason in UIL by defining a procedures list. Just as
with other list types, procedures lists can be defined in-line or in a list section and referenced by
name.

If you define a reason more than once (for example, when the reason is defined both in a referenced
procedures list and in the callbacks list for the object), previous definitions are overridden by the
latest definition. The syntax for a procedures list is as follows:

LIST
list_name: PROCEDURES {
procedure_name [ ( [ value_expression ]) ];
[...] }
[...]

When specifying a widget name as a procedure value expression you must also specify the type of the
widget and a space before the name of the widget.

Object Sections
"UIL" "object section" An object section consists of the keyword OBJECT followed by a sequence of object
declarations. It has the following syntax:

OBJECT object_name:
[ EXPORTED | PRIVATE | IMPORTED ] object_type
[ PROCEDURE creation_function ]
[ object_name [ WIDGET | GADGET ] | {list_definitions } ]

"UIL" "object declaration" Use an object declaration to define the objects that are to be stored in the
UID file. You can reference the object name in declarations that occur elsewhere in the UIL module in any
context where an object name can be used (for example, in a controls list, as a symbolic reference to a
widget ID, or as the tag_value argument for a callback procedure). Objects can be forward referenced;
that is, you can declare an object name after you reference it. All references to an object name must be
consistent with the type of the object, as specified in the object declaration. You can specify an
object as exported, imported, or private.

The object definition can contain a sequence of lists that define the arguments, hierarchy, and callbacks
for the widget. You can specify only one list of each type for an object. When you declare a user-
defined widget, you must include a reference to the widget creation function for the user-defined widget.

Note: Several widgets in the Motif Toolkit actually consist of two linked widgets. For example,
XmScrolledText and XmScrolledList each consist of children XmText and XmList widgets under a
XmScrolledWindow widget. When such a widget is created, its resources are available to both of the
underlying widgets. This can occasionally cause problems, as when the programmer wants a
XmNdestroyCallback routine named to act when the widget is destroyed. In this case, the callback resource
will be available to both sub-widgets, and will cause an error when the widget is destroyed. To avoid
these problems, the programmer should separately create the parent and child widgets, rather than relying
on these linked widgets.

Use the GADGET or WIDGET keyword to specify the object type or to override the default variant for this
object type. You can use the Motif Toolkit name of an object type that has a gadget variant (for
example, XmLabelGadget) as an attribute of an object declaration. The object_type can be any object
type, including gadgets. You need to specify the GADGET or WIDGET keyword only in the declaration of an
object, not when you reference the object. You cannot specify the GADGET or WIDGET keyword for a user-
defined object; user-defined objects are always widgets.

Identifier sections
"UIL" "identifiers" The identifier section allows you to define an identifier, a mechanism that achieves
run-time binding of data to names that appear in a UIL module. The identifier section consists of the
reserved keyword IDENTIFIER, followed by a list of names, each name followed by a semicolon.

IDENTIFIER identifier_name; [...;]

You can later use these names in the UIL module as either the value of an argument to a widget or the tag
value to a callback procedure. At run time, you use the MRM functions MrmRegisterNames and
MrmRegisterNamesInHierarchy to bind the identifier name with the data (or, in the case of callbacks, with
the address of the data) associated with the identifier.

Each UIL module has a single name space; therefore, you cannot use a name you used for a value, object,
or procedure as an identifier name in the same module.

The UIL compiler does not do any type checking on the use of identifiers in a UIL module. Unlike a UIL
value, an identifier does not have a UIL type associated with it. Regardless of what particular type a
widget argument or callback procedure tag is defined to be, you can use an identifier in that context
instead of a value of the corresponding type.

To reference these identifier names in a UIL module, you use the name of the identifier wherever you want
its value to be used.

Include directives
"UIL" "include directive" The include directive incorporates the contents of a specified file into a UIL
module. This mechanism allows several UIL modules to share common definitions. The syntax for the include
directive is as follows:

INCLUDE FILE file_name;

The UIL compiler replaces the include directive with the contents of the include file and processes it as
if these contents had appeared in the current UIL source file.

You can nest include files; that is, an include file can contain include directives. The UIL compiler
can process up to 100 references (including the file containing the UIL module). Therefore, you can
include up to 99 files in a single UIL module, including nested files. Each time a file is opened counts
as a reference, so including the same file twice counts as two references.

The file_name is a simple string containing a file specification that identifies the file to be included.
The rules for finding the specified file are similar to the rules for finding header, or .h files using
the include directive, #include, with a quoted string in C. The UIL uses the -I option for specifying a
search directory for include files.

• If you do not supply a directory, the UIL compiler searches for the include file in the directory
of the main source file.

• If the compiler does not find the include file there, the compiler looks in the same directory as
the source file.

• If you supply a directory, the UIL compiler searches only that directory for the file.

Names and Strings
Names can consist of any of the characters A to Z, a to z, 0 to 9, $ (dollar sign), and _ (underscore).
Names cannot begin with a digit (0 to 9). The maximum length of a name is 31 characters.

UIL gives you a choice of either case-sensitive or case-insensitive names through a clause in the MODULE
header. For example, if names are case sensitive, the names "sample" and "Sample" are distinct from each
other. If names are case insensitive, these names are treated as the same name and can be used
interchangeably. By default, UIL assumes names are case sensitive.

In CASE-INSENSITIVE mode, the compiler outputs all names in the UID file in uppercase form. In CASE-
SENSITIVE mode, names appear in the UIL file exactly as they appear in the source.

The following table lists the reserved keywords, which are not available for defining programmer defined
names. "UIL" "keywords" "UIL module" "keywords" "UIL specification file" "keywords" "Keywords"
┌────────────────────────────────────────────────┐
│ Reserved Keywords │
├────────────────────────────────────────────────┤
│ ARGUMENTS CALLBACKS CONTROLS END │
│ EXPORTED FALSE GADGET IDENTIFIER │
│ INCLUDE LIST MODULE OFF │
│ ON OBJECT PRIVATE PROCEDURE │
│ PROCEDURES TRUE VALUE WIDGET │
└────────────────────────────────────────────────┘

The UIL unreserved keywords are described in the following list and table. These keywords can be used as
programmer defined names, however, if you use any keyword as a name, you cannot use the UIL-supplied
usage of that keyword.

• Built-in argument names (for example, XmNx, XmNheight)

• Built-in reason names (for example, XmNactivateCallback, XmNhelpCallback)

• Character set names (for example, ISO_LATIN1, ISO_HEBREW_LR)

• Constant value names (for example, XmMENU_OPTION, XmBROWSE_SELECT)

• Object types (for example, XmPushButton, XmBulletinBoard)
┌────────────────────────────────────────────────────────────────────────┐
│ Unreserved Keywords │
├────────────────────────────────────────────────────────────────────────┤
│ ANY ARGUMENT ASCIZ_STRING_TABLE │
│ ASCIZ_TABLE BACKGROUND BOOLEAN │
│ CASE_INSENSITIVE CASE_SENSITIVE CHARACTER_SET │
│ COLOR COLOR_TABLE COMPOUND_STRING │
│ COMPOUND_STRING_COMPONENT COMPOUND_STRING_TABLE FILE │
│ FLOAT FONT FONT_TABLE │
│ FONTSET FOREGROUND ICON │
│ IMPORTED INTEGER INTEGER_TABLE │
│ KEYSYM MANAGED NAMES │
│ OBJECTS REASON RGB │
│ RIGHT_TO_LEFT SINGLE_FLOAT STRING │
│ STRING_TABLE TRANSLATION_TABLE UNMANAGED │
│ USER_DEFINED VERSION WIDE_CHARACTER │
│ WIDGET XBITMAPFILE │
└────────────────────────────────────────────────────────────────────────┘

String literals can be composed of the uppercase and lowercase letters, digits, and punctuation
characters. Spaces, tabs, and comments are special elements in the language. They are a means of
delimiting other elements, such as two names. One or more of these elements can appear before or after
any other element in the language. However, spaces, tabs, and comments that appear in string literals
are treated as character sequences rather than delimiters.

Data Types
"UIL" "literals" "UIL module" "literals" "UIL specification file" "literals" "Values" "literals"

UIL provides literals for several of the value types it supports. Some of the value types are not
supported as literals (for example, pixmaps and string tables). You can specify values for these types by
using functions described in the Functions section. UIL directly supports the following literal types:

• String literal

• Integer literal

• Boolean literal

• Floating-point literal

UIL also includes the data type ANY, which is used to turn off compile time checking of data types.

String Literals
"UIL" "string literals" "UIL module" "string literals" "UIL specification file" "string literals"
"Values" "string literals"

A string literal is a sequence of zero or more 8-bit or 16-bit characters or a combination delimited by '
(single quotation marks) or " (double quotation marks). String literals can also contain multibyte
characters delimited with double quotation marks. String literals can be no more than 2000 characters
long.

A single-quoted string literal can span multiple source lines. To continue a single-quoted string
literal, terminate the continued line with a \ (backslash). The literal continues with the first
character on the next line.

Double-quoted string literals cannot span multiple source lines. (Because double-quoted strings can
contain escape sequences and other special characters, you cannot use the backslash character to
designate continuation of the string.) To build a string value that must span multiple source lines, use
the concatenation operator described later in this section.

The syntax of a string literal is one of the following:

'[character_string]'
[#char_set]"[character_string]"

Both string forms associate a character set with a string value. UIL uses the following rules to
determine the character set and storage format for string literals:

• A string declared as 'string' is equivalent to #cur_charset"string", where cur_charset will be the
codeset portion of the value of the LANG environment variable if it is set or the value of
XmFALLBACK_CHARSET if LANG is not set or has no codeset component. By default, XmFALLBACK_CHARSET
is ISO8859-1 (equivalent to ISO_LATIN1), but vendors may define a different default.

• A string declared as "string" is equivalent to #char_set"string" if you specified char_set as the
default character set for the module. If no default character set has been specified for the
module, then if the -s option is provided to the uil command or the use_setlocale_flag is set for
the callable compiler, Uil(), the string will be interpreted to be a string in the current locale.
This means that the string is parsed in the locale of the user by calling setlocale, its charset is
XmFONTLIST_DEFAULT_TAG, and that if the string is converted to a compound string, it is stored as a
locale encoded text segment. Otherwise, "string" is equivalent to #cur_charset"string", where
cur_charset is interpreted as described for single quoted strings.

• A string of the form "string" or #char_set"string" is stored as a null-terminated string.

If the char_set in a string specified in the form above is not a built-in charset, and is not a user-
defined charset, the charset of the string will be set to XmFONTLIST_DEFAULT_TAG, and an informational
message will be issued to the user to note that this substitution has been made.

The following table lists the character sets supported by the UIL compiler for string literals. Note
that several UIL names map to the same character set. In some cases, the UIL name influences how string
literals are read. For example, strings identified by a UIL character set name ending in _LR are read
left-to-right. Names that end in a different number reflect different fonts (for example, ISO_LATIN1 or
ISO_LATIN6). All character sets in this table are represented by 8 bits.
┌───────────────────────────────────────────────────────┐
│ Supported Character Sets │
├───────────────────────────────────────────────────────┤
│ UIL Name Description │
├───────────────────────────────────────────────────────┤
│ ISO_LATIN1 GL: ASCII, GR: Latin-1 Supplement │
│ ISO_LATIN2 GL: ASCII, GR: Latin-2 Supplement │
│ ISO_ARABIC GL: ASCII, GR: Latin-Arabic │
│ Supplement │
│ ISO_LATIN6 GL: ASCII, GR: Latin-Arabic │
│ Supplement │
│ ISO_GREEK GL: ASCII, GR: Latin-Greek Supplement │
│ ISO_LATIN7 GL: ASCII, GR: Latin-Greek Supplement │
│ ISO_HEBREW GL: ASCII, GR: Latin-Hebrew │
│ Supplement │
│ ISO_LATIN8 GL: ASCII, GR: Latin-Hebrew │
│ Supplement │
│ ISO_HEBREW_LR GL: ASCII, GR: Latin-Hebrew │
│ Supplement │
│ ISO_LATIN8_LR GL: ASCII, GR: Latin-Hebrew │
│ Supplement │
│ JIS_KATAKANA GL: JIS Roman, GR: JIS Katakana │
└───────────────────────────────────────────────────────┘

Following are the parsing rules for each of the character sets:

All character sets
Character codes in the range 00...1F, 7F, and 80...9F are control characters including both
bytes of 16-bit characters. The compiler flags these as illegal characters.

ISO_LATIN1 ISO_LATIN2 ISO_LATIN3 ISO_GREEK ISO_LATIN4
These sets are parsed from left to right. The escape sequences for null-terminated strings are
also supported by these character sets.

ISO_HEBREW ISO_ARABIC ISO_LATIN8
These sets are parsed from right to left. For example, the string #ISO_HEBREW"012345" will
generate a primitive string of "543210" with character set ISO_HEBREW. The string direction for
such a string would be right-to-left, so when rendered, the string will appear as "012345." The
escape sequences for null-terminated strings are also supported by these character sets, and
the characters that compose the escape sequences are in left-to-right order. For example, you
would enter \n, not n\.

ISO_HEBREW_LR ISO_ARABIC_LR ISO_LATIN8_LR
These sets are parsed from left to right. For example, the string #ISO_HEBREW_LR"012345"
generates a primitive string "012345" with character set ISO_HEBREW. The string direction for
such a string would still be right-to-left, however, so when rendered, it will appear as
"543210." In other words, the characters were originally typed in the same order in which they
would have been typed in Hebrew (although in Hebrew, the typist would have been using a text
editor that went from right to left). The escape sequences for null-terminated strings are also
supported by these character sets.

JIS_KATAKANA
This set is parsed from left to right. The escape sequences for null-terminated strings are
also supported by this character set. Note that the \ (backslash) may be displayed as a yen
symbol.

In addition to designating parsing rules for strings, character set information remains an attribute of a
compound string. If the string is included in a string consisting of several concatenated segments, the
character set information is included with that string segment. This gives the Motif Toolkit the
information it needs to decipher the compound string and choose a font to display the string.

For an application interface displayed only in English, UIL lets you ignore the distinctions between the
two uses of strings. The compiler recognizes by context when a string must be passed as a null-
terminated string or as a compound string.

The UIL compiler recognizes enough about the various character sets to correctly parse string literals.
The compiler also issues errors if you use a compound string in a context that supports only null-
terminated strings.

Since the character set names are keywords, you must put them in lowercase if case-sensitive names are in
force. If names are case insensitive, character set names can be uppercase, lowercase, or mixed case.

In addition to the built-in character sets recognized by UIL, you can define your own character sets with
the CHARACTER_SET function. You can use the CHARACTER_SET function anywhere a character set can be
specified.

String literals can contain characters with the eighth (high-order) bit set. You cannot type control
characters (00-1F, 7F, and 80-9F) directly in a single-quoted string literal. However, you can represent
these characters with escape sequences. The following list shows the escape sequences for special
characters. "UIL" "escape sequences" "Escape sequences"

\b Backspace

\f Form-feed

\n Newline

\r Carriage return

\t Horizontal tab

\v Vertical tab

\' Single quotation mark

\" Double quotation mark

\\ Backslash

\integer\ Character whose internal representation is given by integer (in the range 0 to 255 decimal)

Note that escape sequences are processed literally in strings that are parsed in the current locale
(localized strings).

The UIL compiler does not process newline characters in compound strings. The effect of a newline
character in a compound string depends only on the character set of the string, and the result is not
guaranteed to be a multiline string.

Compound String Literals

A compound string consists of a string of 8-bit, 16-bit, or multibyte characters, a named character set,
and a writing direction. Its UIL data type is compound_string.

The writing direction of a compound string is implied by the character set specified for the string. You
can explicitly set the writing direction for a compound string by using the COMPOUND_STRING function.

A compound string can consist of a sequence of concatenated compound strings, null-terminated strings, or
a combination of both, each of which can have a different character set property and writing direction.
Use the concatenation operator & (ampersand) to create a sequence of compound strings.

Each string in the sequence is stored, including the character set and writing direction information.

Generally, a string literal is stored in the UID file as a compound string when the literal consists of
concatenated strings having different character sets or writing directions, or when you use the string to
specify a value for an argument that requires a compound string value. If you want to guarantee that a
string literal is stored as a compound string, you must use the COMPOUND_STRING function.

Data Storage Consumption for String Literals

The way a string literal is stored in the UID file depends on how you declare and use the string. The UIL
compiler automatically converts a null-terminated string to a compound string if you use the string to
specify the value of an argument that requires a compound string. However, this conversion is costly in
terms of storage consumption.

PRIVATE, EXPORTED, and IMPORTED string literals require storage for a single allocation when the literal
is declared; thereafter, storage is required for each reference to the literal. Literals declared in-line
require storage for both an allocation and a reference.

The following table summarizes data storage consumption for string literals. The storage requirement for
an allocation consists of a fixed portion and a variable portion. The fixed portion of an allocation is
roughly the same as the storage requirement for a reference (a few bytes). The storage consumed by the
variable portion depends on the size of the literal value (that is, the length of the string). To
conserve storage space, avoid making string literal declarations that result in an allocation per use.
┌──────────────────────────────────────────────┐
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RELATED INFORMATION

       uil(1), Uil(3)

                                                                                                          UIL(5)