Section: User Contributed Perl Documentation (3)
Unicode::GCString - String as Sequence of UAX #29 Grapheme Clusters
$gcstring = Unicode::GCString->new($string);
Unicode::GCString treats Unicode string as a sequence of
extended grapheme clusters
defined by Unicode Standard Annex #29 [UAX
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.
- new (STRING, [KEY => VALUE, ...])
- new (STRING, [LINEBREAK])
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
The first form was introduced by release 2012.10.
Create a copy of grapheme cluster string.
Next position of new string is set at beginning.
Returns number of Unicode characters grapheme cluster string includes,
i.e. length as Unicode string.
Returns total number of columns of grapheme clusters
defined by built-in character database.
For more details see ``DESCRIPTION'' in Unicode::LineBreak.
Returns number of grapheme clusters contained in grapheme cluster string.
Operations as String
Convert grapheme cluster string to Unicode string explicitly.
- cmp (STRING)
- STRING "cmp" STRING
Compare strings. There are no oddities.
One of each STRING may be Unicode string.
- concat (STRING)
- STRING "." STRING
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
Next position of new string is that set on the left value.
- join ([STRING, ...])
Join STRINGs inserting grapheme cluster string.
Any of STRINGs may be Unicode string.
- substr (OFFSET, [LENGTH, [REPLACEMENT]])
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.
This method cannot return the lvalue, unlike built-in substr().
Operations as Sequence of Grapheme Clusters
Convert grapheme cluster string to an array of grapheme clusters.
Test if current position is at end of grapheme cluster string.
- item ([OFFSET])
Returns OFFSET-th grapheme cluster.
If OFFSET was not specified, returns next grapheme cluster.
Instance method, iterative.
Returns next grapheme cluster and increment next position.
- pos ([OFFSET])
If optional OFFSET is specified, set next position by it.
Returns next position of grapheme cluster string.
Returns Line Breaking Class (See Unicode::LineBreak) of the first
character of first grapheme cluster.
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.
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);
$sub = substr("$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.
- 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.
Mark Davis (ed.) (2009-2013).
Unicode Standard Annex #29: Unicode Text Segmentation
, Revisions 15-23.
Hatuka*nezumi - IKEDA
Copyright (C) 2009-2013 Hatuka*nezumi - IKEDA
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.