NAME

       Unicode::GCString - String as Sequence of UAX #29 Grapheme Clusters

SYNOPSIS

           use Unicode::GCString;
           $gcstring = Unicode::GCString->new($string);

DESCRIPTION

       Unicode::GCString treats Unicode string as a sequence of extended grapheme clusters defined by Unicode
       Standard Annex #29 [UAX #29].

       Grapheme cluster is a sequence of Unicode character(s) that consists of one grapheme base and optional
       grapheme extender and/or “prepend” character.  It is close in that people consider as character.

   Public Interface
       Constructors

       new (STRING, [KEY => VALUE, ...])
       new (STRING, [LINEBREAK])
           Constructor.   Create  new  grapheme  cluster  string  (Unicode::GCString object) from Unicode string
           STRING.

           About  optional  KEY  =>  VALUE  pairs  see  "Options"  in  Unicode::LineBreak.   On   second   form,
           Unicode::LineBreak object LINEBREAK controls breaking features.

           Note: The first form was introduced by release 2012.10.

       copy
           Copy  constructor.   Create a copy of grapheme cluster string.  Next position of new string is set at
           beginning.

       Sizes

       chars
           Instance method.  Returns number of Unicode characters grapheme cluster string includes, i.e.  length
           as Unicode string.

       columns
           Instance  method.  Returns total number of columns of grapheme clusters defined by built-in character
           database.  For more details see "DESCRIPTION" in Unicode::LineBreak.

       length
           Instance method.  Returns number of grapheme clusters contained in grapheme cluster string.

       Operations as String

       as_string
       """OBJECT"""
           Instance method.  Convert grapheme cluster string to Unicode string explicitly.

       cmp (STRING)
       STRING "cmp" STRING
           Instance method.  Compare strings.  There are no oddities.  One of each STRING may be Unicode string.

       concat (STRING)
       STRING "." STRING
           Instance method.  Concatenate STRINGs.  One of each STRING may be Unicode string.  Note  that  number
           of  columns  (see  columns())  or  grapheme clusters (see length()) of resulting string is not always
           equal to sum of both strings.  Next position of new string is that set on the left value.

       join ([STRING, ...])
           Instance method.  Join STRINGs inserting grapheme cluster string.  Any  of  STRINGs  may  be  Unicode
           string.

       substr (OFFSET, [LENGTH, [REPLACEMENT]])
           Instance  method.   Returns  substring  of  grapheme  cluster string.  OFFSET and LENGTH are based on
           grapheme clusters.  If REPLACEMENT is specified, substring is replaced by  it.   REPLACEMENT  may  be
           Unicode string.

           Note: This method cannot return the lvalue, unlike built-in substr().

       Operations as Sequence of Grapheme Clusters

       as_array
       "@{"OBJECT"}"
       as_arrayref
           Instance method.  Convert grapheme cluster string to an array of grapheme clusters.

       eos Instance method.  Test if current position is at end of grapheme cluster string.

       item ([OFFSET])
           Instance  method.   Returns  OFFSET-th  grapheme  cluster.  If OFFSET was not specified, returns next
           grapheme cluster.

       next
       "<"OBJECT">"
           Instance method, iterative.  Returns next grapheme cluster and increment next position.

       pos ([OFFSET])
           Instance method.  If optional OFFSET is specified, set next position by it.  Returns next position of
           grapheme cluster string.

       Miscelaneous

       lbc Instance method.  Returns Line Breaking Class (See Unicode::LineBreak)  of  the  first  character  of
           first grapheme cluster.

       lbcext
           Instance  method.  Returns Line Breaking Class (See Unicode::LineBreak) of the last grapheme extender
           of last grapheme cluster.  If there are no grapheme extenders or its  class  is  CM,  value  of  last
           grapheme base will be returned.

CAVEATS

       •   The grapheme cluster should not be referred to as "grapheme" even though Larry does.

       •   On  Perl around 5.10.1, implicit conversion from Unicode::GCString object to Unicode string sometimes
           let "utf8_mg_pos_cache_update" cache be confused.

           For example, instead of doing

               $sub = substr($gcstring, $i, $j);

           do

               $sub = substr("$gcstring", $i, $j);

               $sub = substr($gcstring->as_string, $i, $j);

       •   This module implements default algorithm for  determining  grapheme  cluster  boundaries.   Tailoring
           mechanism has not been supported yet.

VERSION

       Consult $VERSION variable.

   Incompatible Changes
       Release 2013.10
           •   The  new()  method  can  take  non-Unicode  string  argument.  In this case it will be decoded by
               iso-8859-1 (Latin 1) character set.  That method of former releases would  die  with  non-Unicode
               inputs.

SEE ALSO

       [UAX #29] Mark Davis (ed.) (2009-2013).  Unicode Standard Annex #29: Unicode Text Segmentation, Revisions
       15-23.  <http://www.unicode.org/reports/tr29/>.

AUTHOR

       Hatuka*nezumi - IKEDA Soji <hatuka(at)nezumi.nu>

COPYRIGHT

       Copyright (C) 2009-2013 Hatuka*nezumi - IKEDA Soji.

       This  program  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.

perl v5.38.2                                       2024-03-31                             Unicode::GCString(3pm)