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Unicode::GCString(3pm) User Contributed Perl Documentation Unicode::GCString(3pm)
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 XprependX 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 v5.20.2 2017-04-11 Unicode::GCString(3pm)
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