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129.\" ========================================================================
130.\"
131.IX Title "Unicode::Collate 3"
132.TH Unicode::Collate 3 "2002-06-01" "perl v5.8.0" "Perl Programmers Reference Guide"
133.SH "NAME"
134Unicode::Collate \- Unicode Collation Algorithm
135.SH "SYNOPSIS"
136.IX Header "SYNOPSIS"
137.Vb 1
138\& use Unicode::Collate;
139.Ve
140.PP
141.Vb 2
142\& #construct
143\& $Collator = Unicode::Collate->new(%tailoring);
144.Ve
145.PP
146.Vb 2
147\& #sort
148\& @sorted = $Collator->sort(@not_sorted);
149.Ve
150.PP
151.Vb 2
152\& #compare
153\& $result = $Collator->cmp($a, $b); # returns 1, 0, or -1.
154.Ve
155.SH "DESCRIPTION"
156.IX Header "DESCRIPTION"
157.Sh "Constructor and Tailoring"
158.IX Subsection "Constructor and Tailoring"
159The \f(CW\*(C`new\*(C'\fR method returns a collator object.
160.PP
161.Vb 20
162\& $Collator = Unicode::Collate->new(
163\& alternate => $alternate,
164\& backwards => $levelNumber, # or \e@levelNumbers
165\& entry => $element,
166\& normalization => $normalization_form,
167\& ignoreName => qr/$ignoreName/,
168\& ignoreChar => qr/$ignoreChar/,
169\& katakana_before_hiragana => $bool,
170\& level => $collationLevel,
171\& overrideCJK => \e&overrideCJK,
172\& overrideHangul => \e&overrideHangul,
173\& preprocess => \e&preprocess,
174\& rearrange => \e@charList,
175\& table => $filename,
176\& undefName => qr/$undefName/,
177\& undefChar => qr/$undefChar/,
178\& upper_before_lower => $bool,
179\& );
180\& # if %tailoring is false (i.e. empty),
181\& # $Collator should do the default collation.
182.Ve
183.IP "alternate" 4
184.IX Item "alternate"
185\&\-\- see 3.2.2 Alternate Weighting, \s-1UTR\s0 #10.
186.Sp
187This key allows to alternate weighting for variable collation elements,
188which are marked with an \s-1ASTERISK\s0 in the table
189(\s-1NOTE:\s0 Many punction marks and symbols are variable in \fIallkeys.txt\fR).
190.Sp
191.Vb 1
192\& alternate => 'blanked', 'non-ignorable', 'shifted', or 'shift-trimmed'.
193.Ve
194.Sp
195These names are case\-insensitive.
196By default (if specification is omitted), 'shifted' is adopted.
197.Sp
198.Vb 2
199\& 'Blanked' Variable elements are ignorable at levels 1 through 3;
200\& considered at the 4th level.
201.Ve
202.Sp
203.Vb 1
204\& 'Non-ignorable' Variable elements are not reset to ignorable.
205.Ve
206.Sp
207.Vb 3
208\& 'Shifted' Variable elements are ignorable at levels 1 through 3
209\& their level 4 weight is replaced by the old level 1 weight.
210\& Level 4 weight for Non-Variable elements is 0xFFFF.
211.Ve
212.Sp
213.Vb 2
214\& 'Shift-Trimmed' Same as 'shifted', but all FFFF's at the 4th level
215\& are trimmed.
216.Ve
217.IP "backwards" 4
218.IX Item "backwards"
219\&\-\- see 3.1.2 French Accents, \s-1UTR\s0 #10.
220.Sp
221.Vb 1
222\& backwards => $levelNumber or \e@levelNumbers
223.Ve
224.Sp
225Weights in reverse order; ex. level 2 (diacritic ordering) in French.
226If omitted, forwards at all the levels.
227.IP "entry" 4
228.IX Item "entry"
229\&\-\- see 3.1 Linguistic Features; 3.2.1 File Format, \s-1UTR\s0 #10.
230.Sp
231Overrides a default order or defines additional collation elements
232.Sp
233.Vb 5
234\& entry => <<'ENTRIES', # use the UCA file format
235\&00E6 ; [.0861.0020.0002.00E6] [.08B1.0020.0002.00E6] # ligature <ae> as <a><e>
236\&0063 0068 ; [.0893.0020.0002.0063] # "ch" in traditional Spanish
237\&0043 0068 ; [.0893.0020.0008.0043] # "Ch" in traditional Spanish
238\&ENTRIES
239.Ve
240.IP "ignoreName" 4
241.IX Item "ignoreName"
242.PD 0
243.IP "ignoreChar" 4
244.IX Item "ignoreChar"
245.PD
246\&\-\- see Completely Ignorable, 3.2.2 Alternate Weighting, \s-1UTR\s0 #10.
247.Sp
248Makes the entry in the table ignorable.
249If a collation element is ignorable,
250it is ignored as if the element had been deleted from there.
251.Sp
252E.g. when 'a' and 'e' are ignorable,
253\&'element' is equal to 'lament' (or 'lmnt').
254.IP "level" 4
255.IX Item "level"
256\&\-\- see 4.3 Form a sort key for each string, \s-1UTR\s0 #10.
257.Sp
258Set the maximum level.
259Any higher levels than the specified one are ignored.
260.Sp
261.Vb 4
262\& Level 1: alphabetic ordering
263\& Level 2: diacritic ordering
264\& Level 3: case ordering
265\& Level 4: tie-breaking (e.g. in the case when alternate is 'shifted')
266.Ve
267.Sp
268.Vb 1
269\& ex.level => 2,
270.Ve
271.Sp
272If omitted, the maximum is the 4th.
273.IP "normalization" 4
274.IX Item "normalization"
275\&\-\- see 4.1 Normalize each input string, \s-1UTR\s0 #10.
276.Sp
277If specified, strings are normalized before preparation of sort keys
278(the normalization is executed after preprocess).
279.Sp
280As a form name, one of the following names must be used.
281.Sp
282.Vb 4
283\& 'C' or 'NFC' for Normalization Form C
284\& 'D' or 'NFD' for Normalization Form D
285\& 'KC' or 'NFKC' for Normalization Form KC
286\& 'KD' or 'NFKD' for Normalization Form KD
287.Ve
288.Sp
289If omitted, the string is put into Normalization Form D.
290.Sp
291If \f(CW\*(C`undef\*(C'\fR is passed explicitly as the value for this key,
292any normalization is not carried out (this may make tailoring easier
293if any normalization is not desired).
294.Sp
295see \fB\s-1CAVEAT\s0\fR.
296.IP "overrideCJK" 4
297.IX Item "overrideCJK"
298\&\-\- see 7.1 Derived Collation Elements, \s-1UTR\s0 #10.
299.Sp
300By default, mapping of \s-1CJK\s0 Unified Ideographs
301uses the Unicode codepoint order.
302But the mapping of \s-1CJK\s0 Unified Ideographs may be overrided.
303.Sp
304ex. \s-1CJK\s0 Unified Ideographs in the \s-1JIS\s0 code point order.
305.Sp
306.Vb 7
307\& overrideCJK => sub {
308\& my $u = shift; # get a Unicode codepoint
309\& my $b = pack('n', $u); # to UTF-16BE
310\& my $s = your_unicode_to_sjis_converter($b); # convert
311\& my $n = unpack('n', $s); # convert sjis to short
312\& [ $n, 0x20, 0x2, $u ]; # return the collation element
313\& },
314.Ve
315.Sp
316ex. ignores all \s-1CJK\s0 Unified Ideographs.
317.Sp
318.Vb 1
319\& overrideCJK => sub {()}, # CODEREF returning empty list
320.Ve
321.Sp
322.Vb 2
323\& # where ->eq("Pe\ex{4E00}rl", "Perl") is true
324\& # as U+4E00 is a CJK Unified Ideograph and to be ignorable.
325.Ve
326.Sp
327If \f(CW\*(C`undef\*(C'\fR is passed explicitly as the value for this key,
328weights for \s-1CJK\s0 Unified Ideographs are treated as undefined.
329But assignment of weight for \s-1CJK\s0 Unified Ideographs
330in table or entry is still valid.
331.IP "overrideHangul" 4
332.IX Item "overrideHangul"
333\&\-\- see 7.1 Derived Collation Elements, \s-1UTR\s0 #10.
334.Sp
335By default, Hangul Syllables are decomposed into Hangul Jamo.
336But the mapping of Hangul Syllables may be overrided.
337.Sp
338This tag works like overrideCJK, so see there for examples.
339.Sp
340If you want to override the mapping of Hangul Syllables,
341the Normalization Forms D and \s-1KD\s0 are not appropriate
342(they will be decomposed before overriding).
343.Sp
344If \f(CW\*(C`undef\*(C'\fR is passed explicitly as the value for this key,
345weight for Hangul Syllables is treated as undefined
346without decomposition into Hangul Jamo.
347But definition of weight for Hangul Syllables
348in table or entry is still valid.
349.IP "preprocess" 4
350.IX Item "preprocess"
351\&\-\- see 5.1 Preprocessing, \s-1UTR\s0 #10.
352.Sp
353If specified, the coderef is used to preprocess
354before the formation of sort keys.
355.Sp
356ex. dropping English articles, such as \*(L"a\*(R" or \*(L"the\*(R".
357Then, \*(L"the pen\*(R" is before \*(L"a pencil\*(R".
358.Sp
359.Vb 5
360\& preprocess => sub {
361\& my $str = shift;
362\& $str =~ s/\eb(?:an?|the)\es+//gi;
363\& $str;
364\& },
365.Ve
366.IP "rearrange" 4
367.IX Item "rearrange"
368\&\-\- see 3.1.3 Rearrangement, \s-1UTR\s0 #10.
369.Sp
370Characters that are not coded in logical order and to be rearranged.
371By default,
372.Sp
373.Vb 1
374\& rearrange => [ 0x0E40..0x0E44, 0x0EC0..0x0EC4 ],
375.Ve
376.Sp
377If you want to disallow any rearrangement,
378pass \f(CW\*(C`undef\*(C'\fR or \f(CW\*(C`[]\*(C'\fR (a reference to an empty list)
379as the value for this key.
380.IP "table" 4
381.IX Item "table"
382\&\-\- see 3.2 Default Unicode Collation Element Table, \s-1UTR\s0 #10.
383.Sp
384You can use another element table if desired.
385The table file must be in your \f(CW\*(C`lib/Unicode/Collate\*(C'\fR directory.
386.Sp
387By default, the file \f(CW\*(C`lib/Unicode/Collate/allkeys.txt\*(C'\fR is used.
388.Sp
389If \f(CW\*(C`undef\*(C'\fR is passed explicitly as the value for this key,
390no file is read (but you can define collation elements via entry).
391.Sp
392A typical way to define a collation element table
393without any file of table:
394.Sp
395.Vb 11
396\& $onlyABC = Unicode::Collate->new(
397\& table => undef,
398\& entry => << 'ENTRIES',
399\&0061 ; [.0101.0020.0002.0061] # LATIN SMALL LETTER A
400\&0041 ; [.0101.0020.0008.0041] # LATIN CAPITAL LETTER A
401\&0062 ; [.0102.0020.0002.0062] # LATIN SMALL LETTER B
402\&0042 ; [.0102.0020.0008.0042] # LATIN CAPITAL LETTER B
403\&0063 ; [.0103.0020.0002.0063] # LATIN SMALL LETTER C
404\&0043 ; [.0103.0020.0008.0043] # LATIN CAPITAL LETTER C
405\&ENTRIES
406\& );
407.Ve
408.IP "undefName" 4
409.IX Item "undefName"
410.PD 0
411.IP "undefChar" 4
412.IX Item "undefChar"
413.PD
414\&\-\- see 6.3.4 Reducing the Repertoire, \s-1UTR\s0 #10.
415.Sp
416Undefines the collation element as if it were unassigned in the table.
417This reduces the size of the table.
418If an unassigned character appears in the string to be collated,
419the sort key is made from its codepoint
420as a single-character collation element,
421as it is greater than any other assigned collation elements
422(in the codepoint order among the unassigned characters).
423But, it'd be better to ignore characters
424unfamiliar to you and maybe never used.
425.IP "katakana_before_hiragana" 4
426.IX Item "katakana_before_hiragana"
427.PD 0
428.IP "upper_before_lower" 4
429.IX Item "upper_before_lower"
430.PD
431\&\-\- see 6.6 Case Comparisons; 7.3.1 Tertiary Weight Table, \s-1UTR\s0 #10.
432.Sp
433By default, lowercase is before uppercase
434and hiragana is before katakana.
435.Sp
436If the tag is made true, this is reversed.
437.Sp
438\&\fB\s-1NOTE\s0\fR: These tags simplemindedly assume
439any lowercase/uppercase or hiragana/katakana distinctions
440should occur in level 3, and their weights at level 3
441should be same as those mentioned in 7.3.1, \s-1UTR\s0 #10.
442If you define your collation elements which violates this,
443these tags doesn't work validly.
444.Sh "Methods for Collation"
445.IX Subsection "Methods for Collation"
446.ie n .IP """@sorted = $Collator\->sort(@not_sorted)""" 4
447.el .IP "\f(CW@sorted = $Collator\->sort(@not_sorted)\fR" 4
448.IX Item "@sorted = $Collator->sort(@not_sorted)"
449Sorts a list of strings.
450.ie n .IP """$result = $Collator\->cmp($a, $b)""" 4
451.el .IP "\f(CW$result = $Collator\->cmp($a, $b)\fR" 4
452.IX Item "$result = $Collator->cmp($a, $b)"
453Returns 1 (when \f(CW$a\fR is greater than \f(CW$b\fR)
454or 0 (when \f(CW$a\fR is equal to \f(CW$b\fR)
455or \-1 (when \f(CW$a\fR is lesser than \f(CW$b\fR).
456.ie n .IP """$result = $Collator\->eq($a, $b)""" 4
457.el .IP "\f(CW$result = $Collator\->eq($a, $b)\fR" 4
458.IX Item "$result = $Collator->eq($a, $b)"
459.PD 0
460.ie n .IP """$result = $Collator\->ne($a, $b)""" 4
461.el .IP "\f(CW$result = $Collator\->ne($a, $b)\fR" 4
462.IX Item "$result = $Collator->ne($a, $b)"
463.ie n .IP """$result = $Collator\->lt($a, $b)""" 4
464.el .IP "\f(CW$result = $Collator\->lt($a, $b)\fR" 4
465.IX Item "$result = $Collator->lt($a, $b)"
466.ie n .IP """$result = $Collator\->le($a, $b)""" 4
467.el .IP "\f(CW$result = $Collator\->le($a, $b)\fR" 4
468.IX Item "$result = $Collator->le($a, $b)"
469.ie n .IP """$result = $Collator\->gt($a, $b)""" 4
470.el .IP "\f(CW$result = $Collator\->gt($a, $b)\fR" 4
471.IX Item "$result = $Collator->gt($a, $b)"
472.ie n .IP """$result = $Collator\->ge($a, $b)""" 4
473.el .IP "\f(CW$result = $Collator\->ge($a, $b)\fR" 4
474.IX Item "$result = $Collator->ge($a, $b)"
475.PD
476They works like the same name operators as theirs.
477.Sp
478.Vb 6
479\& eq : whether $a is equal to $b.
480\& ne : whether $a is not equal to $b.
481\& lt : whether $a is lesser than $b.
482\& le : whether $a is lesser than $b or equal to $b.
483\& gt : whether $a is greater than $b.
484\& ge : whether $a is greater than $b or equal to $b.
485.Ve
486.ie n .IP """$sortKey = $Collator\->getSortKey($string)""" 4
487.el .IP "\f(CW$sortKey = $Collator\->getSortKey($string)\fR" 4
488.IX Item "$sortKey = $Collator->getSortKey($string)"
489\&\-\- see 4.3 Form a sort key for each string, \s-1UTR\s0 #10.
490.Sp
491Returns a sort key.
492.Sp
493You compare the sort keys using a binary comparison
494and get the result of the comparison of the strings using \s-1UCA\s0.
495.Sp
496.Vb 1
497\& $Collator->getSortKey($a) cmp $Collator->getSortKey($b)
498.Ve
499.Sp
500.Vb 1
501\& is equivalent to
502.Ve
503.Sp
504.Vb 1
505\& $Collator->cmp($a, $b)
506.Ve
507.ie n .IP """$sortKeyForm = $Collator\->viewSortKey($string)""" 4
508.el .IP "\f(CW$sortKeyForm = $Collator\->viewSortKey($string)\fR" 4
509.IX Item "$sortKeyForm = $Collator->viewSortKey($string)"
510Returns a string formalized to display a sort key.
511Weights are enclosed with \f(CW'['\fR and \f(CW']'\fR
512and level boundaries are denoted by \f(CW'|'\fR.
513.Sp
514.Vb 3
515\& use Unicode::Collate;
516\& my $c = Unicode::Collate->new();
517\& print $c->viewSortKey("Perl"),"\en";
518.Ve
519.Sp
520.Vb 3
521\& # output:
522\& # [09B3 08B1 09CB 094F|0020 0020 0020 0020|0008 0002 0002 0002|FFFF FFFF FFFF FFFF]
523\& # Level 1 Level 2 Level 3 Level 4
524.Ve
525.ie n .IP """$position = $Collator\->index($string, $substring)""" 4
526.el .IP "\f(CW$position = $Collator\->index($string, $substring)\fR" 4
527.IX Item "$position = $Collator->index($string, $substring)"
528.PD 0
529.ie n .IP """($position, $length) = $Collator\->index($string, $substring)""" 4
530.el .IP "\f(CW($position, $length) = $Collator\->index($string, $substring)\fR" 4
531.IX Item "($position, $length) = $Collator->index($string, $substring)"
532.PD
533\&\-\- see 6.8 Searching, \s-1UTR\s0 #10.
534.Sp
535If \f(CW$substring\fR matches a part of \f(CW$string\fR, returns
536the position of the first occurrence of the matching part in scalar context;
537in list context, returns a two-element list of
538the position and the length of the matching part.
539.Sp
540\&\fBNotice\fR that the length of the matching part may differ from
541the length of \f(CW$substring\fR.
542.Sp
543\&\fBNote\fR that the position and the length are counted on the string
544after the process of preprocess, normalization, and rearrangement.
545Therefore, in case the specified string is not binary equal to
546the preprocessed/normalized/rearranged string, the position and the length
547may differ form those on the specified string. But it is guaranteed
548that, if matched, it returns a non-negative value as \f(CW$position\fR.
549.Sp
550If \f(CW$substring\fR does not match any part of \f(CW$string\fR,
551returns \f(CW\*(C`\-1\*(C'\fR in scalar context and
552an empty list in list context.
553.Sp
554e.g. you say
555.Sp
556.Vb 7
557\& my $Collator = Unicode::Collate->new( normalization => undef, level => 1 );
558\& my $str = "Ich mu\ex{00DF} studieren.";
559\& my $sub = "m\ex{00FC}ss";
560\& my $match;
561\& if (my($pos,$len) = $Collator->index($str, $sub)) {
562\& $match = substr($str, $pos, $len);
563\& }
564.Ve
565.Sp
566