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¶
- •
- 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.
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.