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, [LINEBREAK])
Constructor. Create new grapheme cluster string (Unicode::GCString object) from Unicode string STRING. Optional Unicode::LineBreak
object LINEBREAK controls breaking features.
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.
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.
Methods palanned to be deprecated
flag ([OFFSET, [VALUE]])
Instance method. Get or set flag value of OFFEST-th grapheme cluster. If OFFSET was not specified, returns flag value of next
grapheme cluster. Flag value is an non-zero integer not greater than 255 and initially is 0.
Predefined flags are:
Unicode::LineBreak::ALLOW_BEFORE
Allow line breaking just before this grapheme cluster.
Unicode::LineBreak::PROHIBIT_BEFORE
Prohibit line breaking just before this grapheme cluster.
lbclass ([OFFSET])
Returns Line Breaking Class (See Unicode::LineBreak) of the first character of OFFSET-th grapheme cluster. If OFFSET was not
specified, returns class of next grapheme cluster.
Note: Use lbc().
lbclass_ext ([OFFSET])
Returns Line Breaking Class (See Unicode::LineBreak) of the last grapheme extender of OFFSET-th grapheme cluster. If there are no
grapheme extenders or its class is CM, value of lbclass() is returned.
Note: Use lbcext().
Miscelaneous
lbc Returns Line Breaking Class (See Unicode::LineBreak) of the first character of first grapheme cluster.
lbcext
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
o The grapheme cluster should not be referred to as "grapheme" even though Larry does.
o 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);
o This module implements default algorithm for determining grapheme cluster boundaries. Tailoring mechanism has not been supported yet.
VERSION
Consult $VERSION variable.
Development versions of this module may be found at http://hatuka.nezumi.nu/repos/Unicode-LineBreak/
<http://hatuka.nezumi.nu/repos/Unicode-LineBreak/>.
SEE ALSO
[UAX #29] Mark Davis (2009-2010). Unicode Standard Annex #29: Unicode Text Segmentation, Revision 15-17.
<http://www.unicode.org/reports/tr29/>.
AUTHOR
Hatuka*nezumi - IKEDA Soji <hatuka(at)nezumi.nu>
COPYRIGHT
Copyright (C) 2009-2012 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 v5.14.2 2012-03-24 Unicode::GCString(3pm)