Unicode::Collate - Unicode Collation Algorithm
use Unicode::Collate;#construct$Collator = Unicode::Collate->new(%tailoring);#sort@sorted = $Collator->sort(@not_sorted);#compare$result = $Collator->cmp($a, $b); # returns 1, 0, or -1.# If %tailoring is false (i.e. empty),# $Collator should do the default collation.This module is an implementation of Unicode Technical Standard #10 (a.k.a. UTS #10) - Unicode Collation Algorithm (a.k.a. UCA).
Thenew method returns a collator object.
$Collator = Unicode::Collate->new( UCA_Version => $UCA_Version, alternate => $alternate, # deprecated: use of 'variable' is recommended. backwards => $levelNumber, # or \@levelNumbers entry => $element, hangul_terminator => $term_primary_weight, ignoreName => qr/$ignoreName/, ignoreChar => qr/$ignoreChar/, katakana_before_hiragana => $bool, level => $collationLevel, normalization => $normalization_form, overrideCJK => \&overrideCJK, overrideHangul => \&overrideHangul, preprocess => \&preprocess, rearrange => \@charList, table => $filename, undefName => qr/$undefName/, undefChar => qr/$undefChar/, upper_before_lower => $bool, variable => $variable,);If the tracking version number of UCA is given, behavior of that tracking version is emulated on collating. If omitted, the return value ofUCA_Version() is used.UCA_Version() should return the latest tracking version supported.
The supported tracking version: 8, 9, 11, or 14.
UCA Unicode Standard DUCET (@version)--------------------------------------------------- 8 3.1 3.0.1 (3.0.1d9) 9 3.1 with Corrigendum 3 3.1.1 (3.1.1)11 4.0 4.0.0 (4.0.0)14 4.1.0 4.1.0 (4.1.0)Note: Recent UTS #10 renames "Tracking Version" to "Revision."
-- see 3.2.2 Alternate Weighting, version 8 of UTS #10
For backward compatibility,alternate (old name) can be used as an alias forvariable.
-- see 3.1.2 French Accents, UTS #10.
backwards => $levelNumber or \@levelNumbersWeights in reverse order; ex. level 2 (diacritic ordering) in French. If omitted, forwards at all the levels.
-- see 3.1 Linguistic Features; 3.2.1 File Format, UTS #10.
If the same character (or a sequence of characters) exists in the collation element table throughtable, mapping to collation elements is overrided. If it does not exist, the mapping is defined additionally.
entry => <<'ENTRY', # for DUCET v4.0.0 (allkeys-4.0.0.txt)0063 0068 ; [.0E6A.0020.0002.0063] # ch0043 0068 ; [.0E6A.0020.0007.0043] # Ch0043 0048 ; [.0E6A.0020.0008.0043] # CH006C 006C ; [.0F4C.0020.0002.006C] # ll004C 006C ; [.0F4C.0020.0007.004C] # Ll004C 004C ; [.0F4C.0020.0008.004C] # LL00F1 ; [.0F7B.0020.0002.00F1] # n-tilde006E 0303 ; [.0F7B.0020.0002.00F1] # n-tilde00D1 ; [.0F7B.0020.0008.00D1] # N-tilde004E 0303 ; [.0F7B.0020.0008.00D1] # N-tildeENTRYentry => <<'ENTRY', # for DUCET v4.0.0 (allkeys-4.0.0.txt)00E6 ; [.0E33.0020.0002.00E6][.0E8B.0020.0002.00E6] # ae ligature as <a><e>00C6 ; [.0E33.0020.0008.00C6][.0E8B.0020.0008.00C6] # AE ligature as <A><E>ENTRYNOTE: The code point in the UCA file format (before';')must be a Unicode code point (defined as hexadecimal), but not a native code point. So0063 must always denoteU+0063, but not a character of"\x63".
Weighting may vary depending on collation element table. So ensure the weights defined inentry will be consistent with those in the collation element table loaded viatable.
In DUCET v4.0.0, primary weight ofC is0E60 and that ofD is0E6D. So setting primary weight ofCH to0E6A (as a value between0E60 and0E6D) makes ordering asC < CH < D. Exactly speaking DUCET already has some characters betweenC andD:small capital C (U+1D04) with primary weight0E64,c-hook/C-hook (U+0188/U+0187) with0E65, andc-curl (U+0255) with0E69. Then primary weight0E6A forCH makesCH ordered betweenc-curl andD.
-- see 7.1.4 Trailing Weights, UTS #10.
If a true value is given (non-zero but should be positive), it will be added as a terminator primary weight to the end of every standard Hangul syllable. Secondary and any higher weights for terminator are set to zero. If the value is false orhangul_terminator key does not exist, insertion of terminator weights will not be performed.
Boundaries of Hangul syllables are determined according to conjoining Jamo behavior inthe Unicode Standard andHangulSyllableType.txt.
Implementation Note: (1) For expansion mapping (Unicode character mapped to a sequence of collation elements), a terminator will not be added between collation elements, even if Hangul syllable boundary exists there. Addition of terminator is restricted to the next position to the last collation element.
(2) Non-conjoining Hangul letters (Compatibility Jamo, halfwidth Jamo, and enclosed letters) are not automatically terminated with a terminator primary weight. These characters may need terminator included in a collation element table beforehand.
-- see 3.2.2 Variable Weighting, UTS #10.
Makes the entry in the table completely ignorable; i.e. as if the weights were zero at all level.
ThroughignoreChar, any character matchingqr/$ignoreChar/ will be ignored. ThroughignoreName, any character whose name (given in thetable file as a comment) matchesqr/$ignoreName/ will be ignored.
E.g. when 'a' and 'e' are ignorable, 'element' is equal to 'lament' (or 'lmnt').
-- see 7.3.1 Tertiary Weight Table, UTS #10.
By default, hiragana is before katakana. If the parameter is made true, this is reversed.
NOTE: This parameter simplemindedly assumes that any hiragana/katakana distinctions must occur in level 3, and their weights at level 3 must be same as those mentioned in 7.3.1, UTS #10. If you define your collation elements which violate this requirement, this parameter does not work validly.
-- see 4.3 Form Sort Key, UTS #10.
Set the maximum level. Any higher levels than the specified one are ignored.
Level 1: alphabetic orderingLevel 2: diacritic orderingLevel 3: case orderingLevel 4: tie-breaking (e.g. in the case when variable is 'shifted')ex.level => 2,If omitted, the maximum is the 4th.
-- see 4.1 Normalize, UTS #10.
If specified, strings are normalized before preparation of sort keys (the normalization is executed after preprocess).
A form nameUnicode::Normalize::normalize() accepts will be applied as$normalization_form. Acceptable names include'NFD','NFC','NFKD', and'NFKC'. SeeUnicode::Normalize::normalize() for detail. If omitted,'NFD' is used.
normalization is performed afterpreprocess (if defined).
Furthermore, special values,undef and"prenormalized", can be used, though they are not concerned withUnicode::Normalize::normalize().
Ifundef (not a string"undef") is passed explicitly as the value for this key, any normalization is not carried out (this may make tailoring easier if any normalization is not desired). Under(normalization => undef), only contiguous contractions are resolved; e.g. even ifA-ring (andA-ring-cedilla) is ordered afterZ,A-cedilla-ring would be primary equal toA. In this point,(normalization => undef, preprocess => sub { NFD(shift) })is not equivalent to(normalization => 'NFD').
In the case of(normalization => "prenormalized"), any normalization is not performed, but non-contiguous contractions with combining characters are performed. Therefore(normalization => 'prenormalized', preprocess => sub { NFD(shift) })is equivalent to(normalization => 'NFD'). If source strings are finely prenormalized,(normalization => 'prenormalized') may save time for normalization.
Except(normalization => undef),Unicode::Normalize is required (see alsoCAVEAT).
-- see 7.1 Derived Collation Elements, UTS #10.
By default, CJK Unified Ideographs are ordered in Unicode codepoint order butCJK Unified Ideographs (ifUCA_Version is 8 to 11, its range isU+4E00..U+9FA5; ifUCA_Version is 14, its range isU+4E00..U+9FBB) are lesser thanCJK Unified Ideographs Extension (its range isU+3400..U+4DB5 andU+20000..U+2A6D6).
ThroughoverrideCJK, ordering of CJK Unified Ideographs can be overrided.
ex. CJK Unified Ideographs in the JIS code point order.
overrideCJK => sub { my $u = shift; # get a Unicode codepoint my $b = pack('n', $u); # to UTF-16BE my $s = your_unicode_to_sjis_converter($b); # convert my $n = unpack('n', $s); # convert sjis to short [ $n, 0x20, 0x2, $u ]; # return the collation element},ex. ignores all CJK Unified Ideographs.
overrideCJK => sub {()}, # CODEREF returning empty list # where ->eq("Pe\x{4E00}rl", "Perl") is true # as U+4E00 is a CJK Unified Ideograph and to be ignorable.Ifundef is passed explicitly as the value for this key, weights for CJK Unified Ideographs are treated as undefined. But assignment of weight for CJK Unified Ideographs in table orentry is still valid.
-- see 7.1 Derived Collation Elements, UTS #10.
By default, Hangul Syllables are decomposed into Hangul Jamo, even if(normalization => undef). But the mapping of Hangul Syllables may be overrided.
This parameter works likeoverrideCJK, so see there for examples.
If you want to override the mapping of Hangul Syllables, NFD, NFKD, and FCD are not appropriate, since they will decompose Hangul Syllables before overriding.
Ifundef is passed explicitly as the value for this key, weight for Hangul Syllables is treated as undefined without decomposition into Hangul Jamo. But definition of weight for Hangul Syllables in table orentry is still valid.
-- see 5.1 Preprocessing, UTS #10.
If specified, the coderef is used to preprocess before the formation of sort keys.
ex. dropping English articles, such as "a" or "the". Then, "the pen" is before "a pencil".
preprocess => sub { my $str = shift; $str =~ s/\b(?:an?|the)\s+//gi; return $str; },preprocess is performed beforenormalization (if defined).
-- see 3.1.3 Rearrangement, UTS #10.
Characters that are not coded in logical order and to be rearranged. IfUCA_Version is equal to or lesser than 11, default is:
rearrange => [ 0x0E40..0x0E44, 0x0EC0..0x0EC4 ],If you want to disallow any rearrangement, passundef or[] (a reference to empty list) as the value for this key.
IfUCA_Version is equal to 14, default is[] (i.e. no rearrangement).
According to the version 9 of UCA, this parameter shall not be used; but it is not warned at present.
-- see 3.2 Default Unicode Collation Element Table, UTS #10.
You can use another collation element table if desired.
The table file should locate in theUnicode/Collate directory on@INC. Say, if the filename isFoo.txt, the table file is searched asUnicode/Collate/Foo.txt in@INC.
By default,allkeys.txt (as the filename of DUCET) is used. If you will prepare your own table file, any name other thanallkeys.txt may be better to avoid namespace conflict.
Ifundef is passed explicitly as the value for this key, no file is read (but you can define collation elements viaentry).
A typical way to define a collation element table without any file of table:
$onlyABC = Unicode::Collate->new( table => undef, entry => << 'ENTRIES',0061 ; [.0101.0020.0002.0061] # LATIN SMALL LETTER A0041 ; [.0101.0020.0008.0041] # LATIN CAPITAL LETTER A0062 ; [.0102.0020.0002.0062] # LATIN SMALL LETTER B0042 ; [.0102.0020.0008.0042] # LATIN CAPITAL LETTER B0063 ; [.0103.0020.0002.0063] # LATIN SMALL LETTER C0043 ; [.0103.0020.0008.0043] # LATIN CAPITAL LETTER CENTRIES );IfignoreName orundefName is used, character names should be specified as a comment (following#) on each line.
-- see 6.3.4 Reducing the Repertoire, UTS #10.
Undefines the collation element as if it were unassigned in the table. This reduces the size of the table. If an unassigned character appears in the string to be collated, the sort key is made from its codepoint as a single-character collation element, as it is greater than any other assigned collation elements (in the codepoint order among the unassigned characters). But, it'd be better to ignore characters unfamiliar to you and maybe never used.
ThroughundefChar, any character matchingqr/$undefChar/ will be undefined. ThroughundefName, any character whose name (given in thetable file as a comment) matchesqr/$undefName/ will be undefined.
ex. Collation weights for beyond-BMP characters are not stored in object:
undefChar => qr/[^\0-\x{fffd}]/,-- see 6.6 Case Comparisons, UTS #10.
By default, lowercase is before uppercase. If the parameter is made true, this is reversed.
NOTE: This parameter simplemindedly assumes that any lowercase/uppercase distinctions must occur in level 3, and their weights at level 3 must be same as those mentioned in 7.3.1, UTS #10. If you define your collation elements which differs from this requirement, this parameter doesn't work validly.
-- see 3.2.2 Variable Weighting, UTS #10.
This key allows to variable weighting for variable collation elements, which are marked with an ASTERISK in the table (NOTE: Many punction marks and symbols are variable inallkeys.txt).
variable => 'blanked', 'non-ignorable', 'shifted', or 'shift-trimmed'.These names are case-insensitive. By default (if specification is omitted), 'shifted' is adopted.
'Blanked' Variable elements are made ignorable at levels 1 through 3; considered at the 4th level.'Non-Ignorable' Variable elements are not reset to ignorable.'Shifted' Variable elements are made ignorable at levels 1 through 3 their level 4 weight is replaced by the old level 1 weight. Level 4 weight for Non-Variable elements is 0xFFFF.'Shift-Trimmed' Same as 'shifted', but all FFFF's at the 4th level are trimmed.@sorted = $Collator->sort(@not_sorted)Sorts a list of strings.
$result = $Collator->cmp($a, $b)Returns 1 (when$a is greater than$b) or 0 (when$a is equal to$b) or -1 (when$a is lesser than$b).
$result = $Collator->eq($a, $b)$result = $Collator->ne($a, $b)$result = $Collator->lt($a, $b)$result = $Collator->le($a, $b)$result = $Collator->gt($a, $b)$result = $Collator->ge($a, $b)They works like the same name operators as theirs.
eq : whether $a is equal to $b.ne : whether $a is not equal to $b.lt : whether $a is lesser than $b.le : whether $a is lesser than $b or equal to $b.gt : whether $a is greater than $b.ge : whether $a is greater than $b or equal to $b.$sortKey = $Collator->getSortKey($string)-- see 4.3 Form Sort Key, UTS #10.
Returns a sort key.
You compare the sort keys using a binary comparison and get the result of the comparison of the strings using UCA.
$Collator->getSortKey($a) cmp $Collator->getSortKey($b) is equivalent to$Collator->cmp($a, $b)$sortKeyForm = $Collator->viewSortKey($string)Converts a sorting key into its representation form. IfUCA_Version is 8, the output is slightly different.
use Unicode::Collate;my $c = Unicode::Collate->new();print $c->viewSortKey("Perl"),"\n";# output:# [0B67 0A65 0B7F 0B03 | 0020 0020 0020 0020 | 0008 0002 0002 0002 | FFFF FFFF FFFF FFFF]# Level 1 Level 2 Level 3 Level 4DISCLAIMER: Ifpreprocess ornormalization parameter is true for$Collator, calling these methods (index,match,gmatch,subst,gsubst) is croaked, as the position and the length might differ from those on the specified string. (Andrearrange andhangul_terminator parameters are neglected.)
Thematch,gmatch,subst,gsubst methods work likem//,m//g,s///,s///g, respectively, but they are not aware of any pattern, but only a literal substring.
$position = $Collator->index($string, $substring[, $position])($position, $length) = $Collator->index($string, $substring[, $position])If$substring matches a part of$string, returns the position of the first occurrence of the matching part in scalar context; in list context, returns a two-element list of the position and the length of the matching part.
If$substring does not match any part of$string, returns-1 in scalar context and an empty list in list context.
e.g. you say
my $Collator = Unicode::Collate->new( normalization => undef, level => 1 ); # (normalization => undef) is REQUIRED.my $str = "Ich muß studieren Perl.";my $sub = "MÜSS";my $match;if (my($pos,$len) = $Collator->index($str, $sub)) { $match = substr($str, $pos, $len);}and get"muß" in$match since"muß" is primary equal to"MÜSS".
$match_ref = $Collator->match($string, $substring)($match) = $Collator->match($string, $substring)If$substring matches a part of$string, in scalar context, returnsa reference to the first occurrence of the matching part ($match_ref is always true if matches, since every reference istrue); in list context, returns the first occurrence of the matching part.
If$substring does not match any part of$string, returnsundef in scalar context and an empty list in list context.
e.g.
if ($match_ref = $Collator->match($str, $sub)) { # scalar contextprint "matches [$$match_ref].\n"; } else {print "doesn't match.\n"; } or if (($match) = $Collator->match($str, $sub)) { # list contextprint "matches [$match].\n"; } else {print "doesn't match.\n"; }@match = $Collator->gmatch($string, $substring)If$substring matches a part of$string, returns all the matching parts (or matching count in scalar context).
If$substring does not match any part of$string, returns an empty list.
$count = $Collator->subst($string, $substring, $replacement)If$substring matches a part of$string, the first occurrence of the matching part is replaced by$replacement ($string is modified) and return$count (always equals to1).
$replacement can be aCODEREF, taking the matching part as an argument, and returning a string to replace the matching part (a bit similar tos/(..)/$coderef->($1)/e).
$count = $Collator->gsubst($string, $substring, $replacement)If$substring matches a part of$string, all the occurrences of the matching part is replaced by$replacement ($string is modified) and return$count.
$replacement can be aCODEREF, taking the matching part as an argument, and returning a string to replace the matching part (a bit similar tos/(..)/$coderef->($1)/eg).
e.g.
my $Collator = Unicode::Collate->new( normalization => undef, level => 1 ); # (normalization => undef) is REQUIRED.my $str = "Camel donkey zebra came\x{301}l CAMEL horse cAm\0E\0L...";$Collator->gsubst($str, "camel", sub { "<b>$_[0]</b>" });# now $str is "<b>Camel</b> donkey zebra <b>came\x{301}l</b> <b>CAMEL</b> horse <b>cAm\0E\0L</b>...";# i.e., all the camels are made bold-faced.%old_tailoring = $Collator->change(%new_tailoring)Change the value of specified keys and returns the changed part.
$Collator = Unicode::Collate->new(level => 4);$Collator->eq("perl", "PERL"); # false%old = $Collator->change(level => 2); # returns (level => 4).$Collator->eq("perl", "PERL"); # true$Collator->change(%old); # returns (level => 2).$Collator->eq("perl", "PERL"); # falseNot all(key,value)s are allowed to be changed. See also@Unicode::Collate::ChangeOK and@Unicode::Collate::ChangeNG.
In the scalar context, returns the modified collator (but it isnot a clone from the original).
$Collator->change(level => 2)->eq("perl", "PERL"); # true$Collator->eq("perl", "PERL"); # true; now max level is 2nd.$Collator->change(level => 4)->eq("perl", "PERL"); # false$version = $Collator->version()Returns the version number (a string) of the Unicode Standard which thetable file used by the collator object is based on. If the table does not include a version line (starting with@version), returns"unknown".
UCA_Version()Returns the tracking version number of UTS #10 this module consults.
Base_Unicode_Version()Returns the version number of UTS #10 this module consults.
No method will be exported.
Though this module can be used without anytable file, to use this module easily, it is recommended to install a table file in the UCA format, by copying it under the directory <a place in @INC>/Unicode/Collate.
The most preferable one is "The Default Unicode Collation Element Table" (aka DUCET), available from the Unicode Consortium's website:
http://www.unicode.org/Public/UCA/http://www.unicode.org/Public/UCA/latest/allkeys.txt (latest version)If DUCET is not installed, it is recommended to copy the file from http://www.unicode.org/Public/UCA/latest/allkeys.txt to <a place in @INC>/Unicode/Collate/allkeys.txt manually.
Use of thenormalization parameter requires theUnicode::Normalize module (seeUnicode::Normalize).
If you need not it (say, in the case when you need not handle any combining characters), assignnormalization => undef explicitly.
-- see 6.5 Avoiding Normalization, UTS #10.
The Conformance Test for the UCA is available underhttp://www.unicode.org/Public/UCA/.
ForCollationTest_SHIFTED.txt, a collator viaUnicode::Collate->new( ) should be used; forCollationTest_NON_IGNORABLE.txt, a collator viaUnicode::Collate->new(variable => "non-ignorable", level => 3).
Unicode::Normalize is required to try The Conformance Test.
The Unicode::Collate module for perl was written by SADAHIRO Tomoyuki, <SADAHIRO@cpan.org>. This module is Copyright(C) 2001-2005, SADAHIRO Tomoyuki. Japan. All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
The file Unicode/Collate/allkeys.txt was copied directly fromhttp://www.unicode.org/Public/UCA/4.1.0/allkeys.txt. This file is Copyright (c) 1991-2005 Unicode, Inc. All rights reserved. Distributed under the Terms of Use inhttp://www.unicode.org/copyright.html.
http://www.unicode.org/Public/UNIDATA/HangulSyllableType.txt
1 POD Error
The following errors were encountered while parsing the POD:
Non-ASCII character seen before =encoding in 'muß'. Assuming CP1252
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