1Unicode::UCD(3pm)      Perl Programmers Reference Guide      Unicode::UCD(3pm)
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3
4

NAME

6       Unicode::UCD - Unicode character database
7

SYNOPSIS

9           use Unicode::UCD 'charinfo';
10           my $charinfo   = charinfo($codepoint);
11
12           use Unicode::UCD 'casefold';
13           my $casefold = casefold(0xFB00);
14
15           use Unicode::UCD 'casespec';
16           my $casespec = casespec(0xFB00);
17
18           use Unicode::UCD 'charblock';
19           my $charblock  = charblock($codepoint);
20
21           use Unicode::UCD 'charscript';
22           my $charscript = charscript($codepoint);
23
24           use Unicode::UCD 'charblocks';
25           my $charblocks = charblocks();
26
27           use Unicode::UCD 'charscripts';
28           my $charscripts = charscripts();
29
30           use Unicode::UCD qw(charscript charinrange);
31           my $range = charscript($script);
32           print "looks like $script\n" if charinrange($range, $codepoint);
33
34           use Unicode::UCD qw(general_categories bidi_types);
35           my $categories = general_categories();
36           my $types = bidi_types();
37
38           use Unicode::UCD 'prop_aliases';
39           my @space_names = prop_aliases("space");
40
41           use Unicode::UCD 'prop_value_aliases';
42           my @gc_punct_names = prop_value_aliases("Gc", "Punct");
43
44           use Unicode::UCD 'prop_invlist';
45           my @puncts = prop_invlist("gc=punctuation");
46
47           use Unicode::UCD 'prop_invmap';
48           my ($list_ref, $map_ref, $format, $missing)
49                                             = prop_invmap("General Category");
50
51           use Unicode::UCD 'compexcl';
52           my $compexcl = compexcl($codepoint);
53
54           use Unicode::UCD 'namedseq';
55           my $namedseq = namedseq($named_sequence_name);
56
57           my $unicode_version = Unicode::UCD::UnicodeVersion();
58
59           my $convert_to_numeric =
60                     Unicode::UCD::num("\N{RUMI DIGIT ONE}\N{RUMI DIGIT TWO}");
61

DESCRIPTION

63       The Unicode::UCD module offers a series of functions that provide a
64       simple interface to the Unicode Character Database.
65
66   code point argument
67       Some of the functions are called with a code point argument, which is
68       either a decimal or a hexadecimal scalar designating a Unicode code
69       point, or "U+" followed by hexadecimals designating a Unicode code
70       point.  In other words, if you want a code point to be interpreted as a
71       hexadecimal number, you must prefix it with either "0x" or "U+",
72       because a string like e.g. 123 will be interpreted as a decimal code
73       point.  Note that the largest code point in Unicode is U+10FFFF.
74
75   charinfo()
76           use Unicode::UCD 'charinfo';
77
78           my $charinfo = charinfo(0x41);
79
80       This returns information about the input "code point argument" as a
81       reference to a hash of fields as defined by the Unicode standard.  If
82       the "code point argument" is not assigned in the standard (i.e., has
83       the general category "Cn" meaning "Unassigned") or is a non-character
84       (meaning it is guaranteed to never be assigned in the standard),
85       "undef" is returned.
86
87       Fields that aren't applicable to the particular code point argument
88       exist in the returned hash, and are empty.
89
90       The keys in the hash with the meanings of their values are:
91
92       code
93           the input "code point argument" expressed in hexadecimal, with
94           leading zeros added if necessary to make it contain at least four
95           hexdigits
96
97       name
98           name of code, all IN UPPER CASE.  Some control-type code points do
99           not have names.  This field will be empty for "Surrogate" and
100           "Private Use" code points, and for the others without a name, it
101           will contain a description enclosed in angle brackets, like
102           "<control>".
103
104       category
105           The short name of the general category of code.  This will match
106           one of the keys in the hash returned by "general_categories()".
107
108           The "prop_value_aliases()" function can be used to get all the
109           synonyms of the category name.
110
111       combining
112           the combining class number for code used in the Canonical Ordering
113           Algorithm.  For Unicode 5.1, this is described in Section 3.11
114           "Canonical Ordering Behavior" available at
115           <http://www.unicode.org/versions/Unicode5.1.0/>
116
117           The "prop_value_aliases()" function can be used to get all the
118           synonyms of the combining class number.
119
120       bidi
121           bidirectional type of code.  This will match one of the keys in the
122           hash returned by "bidi_types()".
123
124           The "prop_value_aliases()" function can be used to get all the
125           synonyms of the bidi type name.
126
127       decomposition
128           is empty if code has no decomposition; or is one or more codes
129           (separated by spaces) that, taken in order, represent a
130           decomposition for code.  Each has at least four hexdigits.  The
131           codes may be preceded by a word enclosed in angle brackets then a
132           space, like "<compat> ", giving the type of decomposition
133
134           This decomposition may be an intermediate one whose components are
135           also decomposable.  Use Unicode::Normalize to get the final
136           decomposition.
137
138       decimal
139           if code is a decimal digit this is its integer numeric value
140
141       digit
142           if code represents some other digit-like number, this is its
143           integer numeric value
144
145       numeric
146           if code represents a whole or rational number, this is its numeric
147           value.  Rational values are expressed as a string like "1/4".
148
149       mirrored
150           "Y" or "N" designating if code is mirrored in bidirectional text
151
152       unicode10
153           name of code in the Unicode 1.0 standard if one existed for this
154           code point and is different from the current name
155
156       comment
157           As of Unicode 6.0, this is always empty.
158
159       upper
160           is empty if there is no single code point uppercase mapping for
161           code (its uppercase mapping is itself); otherwise it is that
162           mapping expressed as at least four hexdigits.  ("casespec()" should
163           be used in addition to charinfo() for case mappings when the
164           calling program can cope with multiple code point mappings.)
165
166       lower
167           is empty if there is no single code point lowercase mapping for
168           code (its lowercase mapping is itself); otherwise it is that
169           mapping expressed as at least four hexdigits.  ("casespec()" should
170           be used in addition to charinfo() for case mappings when the
171           calling program can cope with multiple code point mappings.)
172
173       title
174           is empty if there is no single code point titlecase mapping for
175           code (its titlecase mapping is itself); otherwise it is that
176           mapping expressed as at least four hexdigits.  ("casespec()" should
177           be used in addition to charinfo() for case mappings when the
178           calling program can cope with multiple code point mappings.)
179
180       block
181           the block code belongs to (used in "\p{Blk=...}").  See "Blocks
182           versus Scripts".
183
184       script
185           the script code belongs to.  See "Blocks versus Scripts".
186
187       Note that you cannot do (de)composition and casing based solely on the
188       decomposition, combining, lower, upper, and title fields; you will need
189       also the "compexcl()", and "casespec()" functions.
190
191   charblock()
192           use Unicode::UCD 'charblock';
193
194           my $charblock = charblock(0x41);
195           my $charblock = charblock(1234);
196           my $charblock = charblock(0x263a);
197           my $charblock = charblock("U+263a");
198
199           my $range     = charblock('Armenian');
200
201       With a "code point argument" charblock() returns the block the code
202       point belongs to, e.g.  "Basic Latin".  The old-style block name is
203       returned (see "Old-style versus new-style block names").  If the code
204       point is unassigned, this returns the block it would belong to if it
205       were assigned.
206
207       See also "Blocks versus Scripts".
208
209       If supplied with an argument that can't be a code point, charblock()
210       tries to do the opposite and interpret the argument as an old-style
211       block name. The return value is a range set with one range: an
212       anonymous list with a single element that consists of another anonymous
213       list whose first element is the first code point in the block, and
214       whose second (and final) element is the final code point in the block.
215       (The extra list consisting of just one element is so that the same
216       program logic can be used to handle both this return, and the return
217       from "charscript()" which can have multiple ranges.) You can test
218       whether a code point is in a range using the "charinrange()" function.
219       If the argument is not a known block, "undef" is returned.
220
221   charscript()
222           use Unicode::UCD 'charscript';
223
224           my $charscript = charscript(0x41);
225           my $charscript = charscript(1234);
226           my $charscript = charscript("U+263a");
227
228           my $range      = charscript('Thai');
229
230       With a "code point argument" charscript() returns the script the code
231       point belongs to, e.g.  "Latin", "Greek", "Han".  If the code point is
232       unassigned, it returns "Unknown".
233
234       If supplied with an argument that can't be a code point, charscript()
235       tries to do the opposite and interpret the argument as a script name.
236       The return value is a range set: an anonymous list of lists that
237       contain start-of-range, end-of-range code point pairs. You can test
238       whether a code point is in a range set using the "charinrange()"
239       function. If the argument is not a known script, "undef" is returned.
240
241       See also "Blocks versus Scripts".
242
243   charblocks()
244           use Unicode::UCD 'charblocks';
245
246           my $charblocks = charblocks();
247
248       charblocks() returns a reference to a hash with the known block names
249       as the keys, and the code point ranges (see "charblock()") as the
250       values.
251
252       The names are in the old-style (see "Old-style versus new-style block
253       names").
254
255       prop_invmap("block") can be used to get this same data in a different
256       type of data structure.
257
258       See also "Blocks versus Scripts".
259
260   charscripts()
261           use Unicode::UCD 'charscripts';
262
263           my $charscripts = charscripts();
264
265       charscripts() returns a reference to a hash with the known script names
266       as the keys, and the code point ranges (see "charscript()") as the
267       values.
268
269       prop_invmap("script") can be used to get this same data in a different
270       type of data structure.
271
272       See also "Blocks versus Scripts".
273
274   charinrange()
275       In addition to using the "\p{Blk=...}" and "\P{Blk=...}" constructs,
276       you can also test whether a code point is in the range as returned by
277       "charblock()" and "charscript()" or as the values of the hash returned
278       by "charblocks()" and "charscripts()" by using charinrange():
279
280           use Unicode::UCD qw(charscript charinrange);
281
282           $range = charscript('Hiragana');
283           print "looks like hiragana\n" if charinrange($range, $codepoint);
284
285   general_categories()
286           use Unicode::UCD 'general_categories';
287
288           my $categories = general_categories();
289
290       This returns a reference to a hash which has short general category
291       names (such as "Lu", "Nd", "Zs", "S") as keys and long names (such as
292       "UppercaseLetter", "DecimalNumber", "SpaceSeparator", "Symbol") as
293       values.  The hash is reversible in case you need to go from the long
294       names to the short names.  The general category is the one returned
295       from "charinfo()" under the "category" key.
296
297       The "prop_value_aliases()" function can be used to get all the synonyms
298       of the category name.
299
300   bidi_types()
301           use Unicode::UCD 'bidi_types';
302
303           my $categories = bidi_types();
304
305       This returns a reference to a hash which has the short bidi
306       (bidirectional) type names (such as "L", "R") as keys and long names
307       (such as "Left-to-Right", "Right-to-Left") as values.  The hash is
308       reversible in case you need to go from the long names to the short
309       names.  The bidi type is the one returned from "charinfo()" under the
310       "bidi" key.  For the exact meaning of the various bidi classes the
311       Unicode TR9 is recommended reading:
312       <http://www.unicode.org/reports/tr9/> (as of Unicode 5.0.0)
313
314       The "prop_value_aliases()" function can be used to get all the synonyms
315       of the bidi type name.
316
317   compexcl()
318           use Unicode::UCD 'compexcl';
319
320           my $compexcl = compexcl(0x09dc);
321
322       This routine is included for backwards compatibility, but as of Perl
323       5.12, for most purposes it is probably more convenient to use one of
324       the following instead:
325
326           my $compexcl = chr(0x09dc) =~ /\p{Comp_Ex};
327           my $compexcl = chr(0x09dc) =~ /\p{Full_Composition_Exclusion};
328
329       or even
330
331           my $compexcl = chr(0x09dc) =~ /\p{CE};
332           my $compexcl = chr(0x09dc) =~ /\p{Composition_Exclusion};
333
334       The first two forms return true if the "code point argument" should not
335       be produced by composition normalization.  For the final two forms to
336       return true, it is additionally required that this fact not otherwise
337       be determinable from the Unicode data base.
338
339       This routine behaves identically to the final two forms.  That is, it
340       does not return true if the code point has a decomposition consisting
341       of another single code point, nor if its decomposition starts with a
342       code point whose combining class is non-zero.  Code points that meet
343       either of these conditions should also not be produced by composition
344       normalization, which is probably why you should use the
345       "Full_Composition_Exclusion" property instead, as shown above.
346
347       The routine returns false otherwise.
348
349   casefold()
350           use Unicode::UCD 'casefold';
351
352           my $casefold = casefold(0xDF);
353           if (defined $casefold) {
354               my @full_fold_hex = split / /, $casefold->{'full'};
355               my $full_fold_string =
356                           join "", map {chr(hex($_))} @full_fold_hex;
357               my @turkic_fold_hex =
358                               split / /, ($casefold->{'turkic'} ne "")
359                                               ? $casefold->{'turkic'}
360                                               : $casefold->{'full'};
361               my $turkic_fold_string =
362                               join "", map {chr(hex($_))} @turkic_fold_hex;
363           }
364           if (defined $casefold && $casefold->{'simple'} ne "") {
365               my $simple_fold_hex = $casefold->{'simple'};
366               my $simple_fold_string = chr(hex($simple_fold_hex));
367           }
368
369       This returns the (almost) locale-independent case folding of the
370       character specified by the "code point argument".  (Starting in Perl
371       v5.16, the core function "fc()" returns the "full" mapping (described
372       below) faster than this does, and for entire strings.)
373
374       If there is no case folding for the input code point, "undef" is
375       returned.
376
377       If there is a case folding for that code point, a reference to a hash
378       with the following fields is returned:
379
380       code
381           the input "code point argument" expressed in hexadecimal, with
382           leading zeros added if necessary to make it contain at least four
383           hexdigits
384
385       full
386           one or more codes (separated by spaces) that, taken in order, give
387           the code points for the case folding for code.  Each has at least
388           four hexdigits.
389
390       simple
391           is empty, or is exactly one code with at least four hexdigits which
392           can be used as an alternative case folding when the calling program
393           cannot cope with the fold being a sequence of multiple code points.
394           If full is just one code point, then simple equals full.  If there
395           is no single code point folding defined for code, then simple is
396           the empty string.  Otherwise, it is an inferior, but still better-
397           than-nothing alternative folding to full.
398
399       mapping
400           is the same as simple if simple is not empty, and it is the same as
401           full otherwise.  It can be considered to be the simplest possible
402           folding for code.  It is defined primarily for backwards
403           compatibility.
404
405       status
406           is "C" (for "common") if the best possible fold is a single code
407           point (simple equals full equals mapping).  It is "S" if there are
408           distinct folds, simple and full (mapping equals simple).  And it is
409           "F" if there is only a full fold (mapping equals full; simple is
410           empty).  Note that this describes the contents of mapping.  It is
411           defined primarily for backwards compatibility.
412
413           For Unicode versions between 3.1 and 3.1.1 inclusive, status can
414           also be "I" which is the same as "C" but is a special case for
415           dotted uppercase I and dotless lowercase i:
416
417           * If you use this "I" mapping
418               the result is case-insensitive, but dotless and dotted I's are
419               not distinguished
420
421           * If you exclude this "I" mapping
422               the result is not fully case-insensitive, but dotless and
423               dotted I's are distinguished
424
425       turkic
426           contains any special folding for Turkic languages.  For versions of
427           Unicode starting with 3.2, this field is empty unless code has a
428           different folding in Turkic languages, in which case it is one or
429           more codes (separated by spaces) that, taken in order, give the
430           code points for the case folding for code in those languages.  Each
431           code has at least four hexdigits.  Note that this folding does not
432           maintain canonical equivalence without additional processing.
433
434           For Unicode versions between 3.1 and 3.1.1 inclusive, this field is
435           empty unless there is a special folding for Turkic languages, in
436           which case status is "I", and mapping, full, simple, and turkic are
437           all equal.
438
439       Programs that want complete generality and the best folding results
440       should use the folding contained in the full field.  But note that the
441       fold for some code points will be a sequence of multiple code points.
442
443       Programs that can't cope with the fold mapping being multiple code
444       points can use the folding contained in the simple field, with the loss
445       of some generality.  In Unicode 5.1, about 7% of the defined foldings
446       have no single code point folding.
447
448       The mapping and status fields are provided for backwards compatibility
449       for existing programs.  They contain the same values as in previous
450       versions of this function.
451
452       Locale is not completely independent.  The turkic field contains
453       results to use when the locale is a Turkic language.
454
455       For more information about case mappings see
456       <http://www.unicode.org/unicode/reports/tr21>
457
458   casespec()
459           use Unicode::UCD 'casespec';
460
461           my $casespec = casespec(0xFB00);
462
463       This returns the potentially locale-dependent case mappings of the
464       "code point argument".  The mappings may be longer than a single code
465       point (which the basic Unicode case mappings as returned by
466       "charinfo()" never are).
467
468       If there are no case mappings for the "code point argument", or if all
469       three possible mappings (lower, title and upper) result in single code
470       points and are locale independent and unconditional, "undef" is
471       returned (which means that the case mappings, if any, for the code
472       point are those returned by "charinfo()").
473
474       Otherwise, a reference to a hash giving the mappings (or a reference to
475       a hash of such hashes, explained below) is returned with the following
476       keys and their meanings:
477
478       The keys in the bottom layer hash with the meanings of their values
479       are:
480
481       code
482           the input "code point argument" expressed in hexadecimal, with
483           leading zeros added if necessary to make it contain at least four
484           hexdigits
485
486       lower
487           one or more codes (separated by spaces) that, taken in order, give
488           the code points for the lower case of code.  Each has at least four
489           hexdigits.
490
491       title
492           one or more codes (separated by spaces) that, taken in order, give
493           the code points for the title case of code.  Each has at least four
494           hexdigits.
495
496       upper
497           one or more codes (separated by spaces) that, taken in order, give
498           the code points for the upper case of code.  Each has at least four
499           hexdigits.
500
501       condition
502           the conditions for the mappings to be valid.  If "undef", the
503           mappings are always valid.  When defined, this field is a list of
504           conditions, all of which must be true for the mappings to be valid.
505           The list consists of one or more locales (see below) and/or
506           contexts (explained in the next paragraph), separated by spaces.
507           (Other than as used to separate elements, spaces are to be
508           ignored.)  Case distinctions in the condition list are not
509           significant.  Conditions preceded by "NON_" represent the negation
510           of the condition.
511
512           A context is one of those defined in the Unicode standard.  For
513           Unicode 5.1, they are defined in Section 3.13 "Default Case
514           Operations" available at
515           <http://www.unicode.org/versions/Unicode5.1.0/>.  These are for
516           context-sensitive casing.
517
518       The hash described above is returned for locale-independent casing,
519       where at least one of the mappings has length longer than one.  If
520       "undef" is returned, the code point may have mappings, but if so, all
521       are length one, and are returned by "charinfo()".  Note that when this
522       function does return a value, it will be for the complete set of
523       mappings for a code point, even those whose length is one.
524
525       If there are additional casing rules that apply only in certain
526       locales, an additional key for each will be defined in the returned
527       hash.  Each such key will be its locale name, defined as a 2-letter ISO
528       3166 country code, possibly followed by a "_" and a 2-letter ISO
529       language code (possibly followed by a "_" and a variant code).  You can
530       find the lists of all possible locales, see Locale::Country and
531       Locale::Language.  (In Unicode 6.0, the only locales returned by this
532       function are "lt", "tr", and "az".)
533
534       Each locale key is a reference to a hash that has the form above, and
535       gives the casing rules for that particular locale, which take
536       precedence over the locale-independent ones when in that locale.
537
538       If the only casing for a code point is locale-dependent, then the
539       returned hash will not have any of the base keys, like "code", "upper",
540       etc., but will contain only locale keys.
541
542       For more information about case mappings see
543       <http://www.unicode.org/unicode/reports/tr21/>
544
545   namedseq()
546           use Unicode::UCD 'namedseq';
547
548           my $namedseq = namedseq("KATAKANA LETTER AINU P");
549           my @namedseq = namedseq("KATAKANA LETTER AINU P");
550           my %namedseq = namedseq();
551
552       If used with a single argument in a scalar context, returns the string
553       consisting of the code points of the named sequence, or "undef" if no
554       named sequence by that name exists.  If used with a single argument in
555       a list context, it returns the list of the ordinals of the code points.
556       If used with no arguments in a list context, returns a hash with the
557       names of the named sequences as the keys and the named sequences as
558       strings as the values.  Otherwise, it returns "undef" or an empty list
559       depending on the context.
560
561       This function only operates on officially approved (not provisional)
562       named sequences.
563
564       Note that as of Perl 5.14, "\N{KATAKANA LETTER AINU P}" will insert the
565       named sequence into double-quoted strings, and
566       "charnames::string_vianame("KATAKANA LETTER AINU P")" will return the
567       same string this function does, but will also operate on character
568       names that aren't named sequences, without you having to know which are
569       which.  See charnames.
570
571   num()
572           use Unicode::UCD 'num';
573
574           my $val = num("123");
575           my $one_quarter = num("\N{VULGAR FRACTION 1/4}");
576
577       "num" returns the numeric value of the input Unicode string; or "undef"
578       if it doesn't think the entire string has a completely valid, safe
579       numeric value.
580
581       If the string is just one character in length, the Unicode numeric
582       value is returned if it has one, or "undef" otherwise.  Note that this
583       need not be a whole number.  "num("\N{TIBETAN DIGIT HALF ZERO}")", for
584       example returns -0.5.
585
586       If the string is more than one character, "undef" is returned unless
587       all its characters are decimal digits (that is, they would match
588       "\d+"), from the same script.  For example if you have an ASCII '0' and
589       a Bengali '3', mixed together, they aren't considered a valid number,
590       and "undef" is returned.  A further restriction is that the digits all
591       have to be of the same form.  A half-width digit mixed with a full-
592       width one will return "undef".  The Arabic script has two sets of
593       digits;  "num" will return "undef" unless all the digits in the string
594       come from the same set.
595
596       "num" errs on the side of safety, and there may be valid strings of
597       decimal digits that it doesn't recognize.  Note that Unicode defines a
598       number of "digit" characters that aren't "decimal digit" characters.
599       "Decimal digits" have the property that they have a positional value,
600       i.e., there is a units position, a 10's position, a 100's, etc, AND
601       they are arranged in Unicode in blocks of 10 contiguous code points.
602       The Chinese digits, for example, are not in such a contiguous block,
603       and so Unicode doesn't view them as decimal digits, but merely digits,
604       and so "\d" will not match them.  A single-character string containing
605       one of these digits will have its decimal value returned by "num", but
606       any longer string containing only these digits will return "undef".
607
608       Strings of multiple sub- and superscripts are not recognized as
609       numbers.  You can use either of the compatibility decompositions in
610       Unicode::Normalize to change these into digits, and then call "num" on
611       the result.
612
613   prop_aliases()
614           use Unicode::UCD 'prop_aliases';
615
616           my ($short_name, $full_name, @other_names) = prop_aliases("space");
617           my $same_full_name = prop_aliases("Space");     # Scalar context
618           my ($same_short_name) = prop_aliases("Space");  # gets 0th element
619           print "The full name is $full_name\n";
620           print "The short name is $short_name\n";
621           print "The other aliases are: ", join(", ", @other_names), "\n";
622
623           prints:
624           The full name is White_Space
625           The short name is WSpace
626           The other aliases are: Space
627
628       Most Unicode properties have several synonymous names.  Typically,
629       there is at least a short name, convenient to type, and a long name
630       that more fully describes the property, and hence is more easily
631       understood.
632
633       If you know one name for a Unicode property, you can use "prop_aliases"
634       to find either the long name (when called in scalar context), or a list
635       of all of the names, somewhat ordered so that the short name is in the
636       0th element, the long name in the next element, and any other synonyms
637       are in the remaining elements, in no particular order.
638
639       The long name is returned in a form nicely capitalized, suitable for
640       printing.
641
642       The input parameter name is loosely matched, which means that white
643       space, hyphens, and underscores are ignored (except for the trailing
644       underscore in the old_form grandfathered-in "L_", which is better
645       written as "LC", and both of which mean "General_Category=Cased
646       Letter").
647
648       If the name is unknown, "undef" is returned (or an empty list in list
649       context).  Note that Perl typically recognizes property names in
650       regular expressions with an optional ""Is_"" (with or without the
651       underscore) prefixed to them, such as "\p{isgc=punct}".  This function
652       does not recognize those in the input, returning "undef".  Nor are they
653       included in the output as possible synonyms.
654
655       "prop_aliases" does know about the Perl extensions to Unicode
656       properties, such as "Any" and "XPosixAlpha", and the single form
657       equivalents to Unicode properties such as "XDigit", "Greek",
658       "In_Greek", and "Is_Greek".  The final example demonstrates that the
659       "Is_" prefix is recognized for these extensions; it is needed to
660       resolve ambiguities.  For example, "prop_aliases('lc')" returns the
661       list "(lc, Lowercase_Mapping)", but "prop_aliases('islc')" returns
662       "(Is_LC, Cased_Letter)".  This is because "islc" is a Perl extension
663       which is short for "General_Category=Cased Letter".  The lists returned
664       for the Perl extensions will not include the "Is_" prefix (whether or
665       not the input had it) unless needed to resolve ambiguities, as shown in
666       the "islc" example, where the returned list had one element containing
667       "Is_", and the other without.
668
669       It is also possible for the reverse to happen:  "prop_aliases('isc')"
670       returns the list "(isc, ISO_Comment)"; whereas "prop_aliases('c')"
671       returns "(C, Other)" (the latter being a Perl extension meaning
672       "General_Category=Other".  "Properties accessible through Unicode::UCD"
673       in perluniprops lists the available forms, including which ones are
674       discouraged from use.
675
676       Those discouraged forms are accepted as input to "prop_aliases", but
677       are not returned in the lists.  "prop_aliases('isL&')" and
678       "prop_aliases('isL_')", which are old synonyms for "Is_LC" and should
679       not be used in new code, are examples of this.  These both return
680       "(Is_LC, Cased_Letter)".  Thus this function allows you to take a
681       discourarged form, and find its acceptable alternatives.  The same goes
682       with single-form Block property equivalences.  Only the forms that
683       begin with "In_" are not discouraged; if you pass "prop_aliases" a
684       discouraged form, you will get back the equivalent ones that begin with
685       "In_".  It will otherwise look like a new-style block name (see.  "Old-
686       style versus new-style block names").
687
688       "prop_aliases" does not know about any user-defined properties, and
689       will return "undef" if called with one of those.  Likewise for Perl
690       internal properties, with the exception of "Perl_Decimal_Digit" which
691       it does know about (and which is documented below in "prop_invmap()").
692
693   prop_value_aliases()
694           use Unicode::UCD 'prop_value_aliases';
695
696           my ($short_name, $full_name, @other_names)
697                                          = prop_value_aliases("Gc", "Punct");
698           my $same_full_name = prop_value_aliases("Gc", "P");   # Scalar cntxt
699           my ($same_short_name) = prop_value_aliases("Gc", "P"); # gets 0th
700                                                                  # element
701           print "The full name is $full_name\n";
702           print "The short name is $short_name\n";
703           print "The other aliases are: ", join(", ", @other_names), "\n";
704
705           prints:
706           The full name is Punctuation
707           The short name is P
708           The other aliases are: Punct
709
710       Some Unicode properties have a restricted set of legal values.  For
711       example, all binary properties are restricted to just "true" or
712       "false"; and there are only a few dozen possible General Categories.
713
714       For such properties, there are usually several synonyms for each
715       possible value.  For example, in binary properties, truth can be
716       represented by any of the strings "Y", "Yes", "T", or "True"; and the
717       General Category "Punctuation" by that string, or "Punct", or simply
718       "P".
719
720       Like property names, there is typically at least a short name for each
721       such property-value, and a long name.  If you know any name of the
722       property-value, you can use "prop_value_aliases"() to get the long name
723       (when called in scalar context), or a list of all the names, with the
724       short name in the 0th element, the long name in the next element, and
725       any other synonyms in the remaining elements, in no particular order,
726       except that any all-numeric synonyms will be last.
727
728       The long name is returned in a form nicely capitalized, suitable for
729       printing.
730
731       Case, white space, hyphens, and underscores are ignored in the input
732       parameters (except for the trailing underscore in the old-form
733       grandfathered-in general category property value "L_", which is better
734       written as "LC").
735
736       If either name is unknown, "undef" is returned.  Note that Perl
737       typically recognizes property names in regular expressions with an
738       optional ""Is_"" (with or without the underscore) prefixed to them,
739       such as "\p{isgc=punct}".  This function does not recognize those in
740       the property parameter, returning "undef".
741
742       If called with a property that doesn't have synonyms for its values, it
743       returns the input value, possibly normalized with capitalization and
744       underscores.
745
746       For the block property, new-style block names are returned (see "Old-
747       style versus new-style block names").
748
749       To find the synonyms for single-forms, such as "\p{Any}", use
750       "prop_aliases()" instead.
751
752       "prop_value_aliases" does not know about any user-defined properties,
753       and will return "undef" if called with one of those.
754
755   prop_invlist()
756       "prop_invlist" returns an inversion list (described below) that defines
757       all the code points for the binary Unicode property (or
758       "property=value" pair) given by the input parameter string:
759
760        use feature 'say';
761        use Unicode::UCD 'prop_invlist';
762        say join ", ", prop_invlist("Any");
763
764        prints:
765        0, 1114112
766
767       An empty list is returned if the input is unknown; the number of
768       elements in the list is returned if called in scalar context.
769
770       perluniprops gives the list of properties that this function accepts,
771       as well as all the possible forms for them (including with the optional
772       "Is_" prefixes).  (Except this function doesn't accept any Perl-
773       internal properties, some of which are listed there.) This function
774       uses the same loose or tighter matching rules for resolving the input
775       property's name as is done for regular expressions.  These are also
776       specified in perluniprops.  Examples of using the "property=value" form
777       are:
778
779        say join ", ", prop_invlist("Script=Shavian");
780
781        prints:
782        66640, 66688
783
784        say join ", ", prop_invlist("ASCII_Hex_Digit=No");
785
786        prints:
787        0, 48, 58, 65, 71, 97, 103
788
789        say join ", ", prop_invlist("ASCII_Hex_Digit=Yes");
790
791        prints:
792        48, 58, 65, 71, 97, 103
793
794       Inversion lists are a compact way of specifying Unicode property-value
795       definitions.  The 0th item in the list is the lowest code point that
796       has the property-value.  The next item (item [1]) is the lowest code
797       point beyond that one that does NOT have the property-value.  And the
798       next item beyond that ([2]) is the lowest code point beyond that one
799       that does have the property-value, and so on.  Put another way, each
800       element in the list gives the beginning of a range that has the
801       property-value (for even numbered elements), or doesn't have the
802       property-value (for odd numbered elements).  The name for this data
803       structure stems from the fact that each element in the list toggles (or
804       inverts) whether the corresponding range is or isn't on the list.
805
806       In the final example above, the first ASCII Hex digit is code point 48,
807       the character "0", and all code points from it through 57 (a "9") are
808       ASCII hex digits.  Code points 58 through 64 aren't, but 65 (an "A")
809       through 70 (an "F") are, as are 97 ("a") through 102 ("f").  103 starts
810       a range of code points that aren't ASCII hex digits.  That range
811       extends to infinity, which on your computer can be found in the
812       variable $Unicode::UCD::MAX_CP.  (This variable is as close to infinity
813       as Perl can get on your platform, and may be too high for some
814       operations to work; you may wish to use a smaller number for your
815       purposes.)
816
817       Note that the inversion lists returned by this function can possibly
818       include non-Unicode code points, that is anything above 0x10FFFF.  This
819       is in contrast to Perl regular expression matches on those code points,
820       in which a non-Unicode code point always fails to match.  For example,
821       both of these have the same result:
822
823        chr(0x110000) =~ \p{ASCII_Hex_Digit=True}      # Fails.
824        chr(0x110000) =~ \p{ASCII_Hex_Digit=False}     # Fails!
825
826       And both raise a warning that a Unicode property is being used on a
827       non-Unicode code point.  It is arguable as to which is the correct
828       thing to do here.  This function has chosen the way opposite to the
829       Perl regular expression behavior.  This allows you to easily flip to to
830       the Perl regular expression way (for you to go in the other direction
831       would be far harder).  Simply add 0x110000 at the end of the non-empty
832       returned list if it isn't already that value; and pop that value if it
833       is; like:
834
835        my @list = prop_invlist("foo");
836        if (@list) {
837            if ($list[-1] == 0x110000) {
838                pop @list;  # Defeat the turning on for above Unicode
839            }
840            else {
841                push @list, 0x110000; # Turn off for above Unicode
842            }
843        }
844
845       It is a simple matter to expand out an inversion list to a full list of
846       all code points that have the property-value:
847
848        my @invlist = prop_invlist($property_name);
849        die "empty" unless @invlist;
850        my @full_list;
851        for (my $i = 0; $i < @invlist; $i += 2) {
852           my $upper = ($i + 1) < @invlist
853                       ? $invlist[$i+1] - 1      # In range
854                       : $Unicode::UCD::MAX_CP;  # To infinity.  You may want
855                                                 # to stop much much earlier;
856                                                 # going this high may expose
857                                                 # perl deficiencies with very
858                                                 # large numbers.
859           for my $j ($invlist[$i] .. $upper) {
860               push @full_list, $j;
861           }
862        }
863
864       "prop_invlist" does not know about any user-defined nor Perl internal-
865       only properties, and will return "undef" if called with one of those.
866
867   prop_invmap()
868        use Unicode::UCD 'prop_invmap';
869        my ($list_ref, $map_ref, $format, $missing)
870                                             = prop_invmap("General Category");
871
872       "prop_invmap" is used to get the complete mapping definition for a
873       property, in the form of an inversion map.  An inversion map consists
874       of two parallel arrays.  One is an ordered list of code points that
875       mark range beginnings, and the other gives the value (or mapping) that
876       all code points in the corresponding range have.
877
878       "prop_invmap" is called with the name of the desired property.  The
879       name is loosely matched, meaning that differences in case, white-space,
880       hyphens, and underscores are not meaningful (except for the trailing
881       underscore in the old-form grandfathered-in property "L_", which is
882       better written as "LC", or even better, "Gc=LC").
883
884       Many Unicode properties have more than one name (or alias).
885       "prop_invmap" understands all of these, including Perl extensions to
886       them.  Ambiguities are resolved as described above for
887       "prop_aliases()".  The Perl internal property "Perl_Decimal_Digit,
888       described below, is also accepted.  "undef" is returned if the property
889       name is unknown.  See "Properties accessible through Unicode::UCD" in
890       perluniprops for the properties acceptable as inputs to this function.
891
892       It is a fatal error to call this function except in list context.
893
894       In addition to the the two arrays that form the inversion map,
895       "prop_invmap" returns two other values; one is a scalar that gives some
896       details as to the format of the entries of the map array; the other is
897       used for specialized purposes, described at the end of this section.
898
899       This means that "prop_invmap" returns a 4 element list.  For example,
900
901        my ($blocks_ranges_ref, $blocks_maps_ref, $format, $default)
902                                                        = prop_invmap("Block");
903
904       In this call, the two arrays will be populated as shown below (for
905       Unicode 6.0):
906
907        Index  @blocks_ranges  @blocks_maps
908          0        0x0000      Basic Latin
909          1        0x0080      Latin-1 Supplement
910          2        0x0100      Latin Extended-A
911          3        0x0180      Latin Extended-B
912          4        0x0250      IPA Extensions
913          5        0x02B0      Spacing Modifier Letters
914          6        0x0300      Combining Diacritical Marks
915          7        0x0370      Greek and Coptic
916          8        0x0400      Cyrillic
917         ...
918        233        0x2B820     No_Block
919        234        0x2F800     CJK Compatibility Ideographs Supplement
920        235        0x2FA20     No_Block
921        236        0xE0000     Tags
922        237        0xE0080     No_Block
923        238        0xE0100     Variation Selectors Supplement
924        239        0xE01F0     No_Block
925        240        0xF0000     Supplementary Private Use Area-A
926        241        0x100000    Supplementary Private Use Area-B
927        242        0x110000    No_Block
928
929       The first line (with Index [0]) means that the value for code point 0
930       is "Basic Latin".  The entry "0x0080" in the @blocks_ranges column in
931       the second line means that the value from the first line, "Basic
932       Latin", extends to all code points in the range from 0 up to but not
933       including 0x0080, that is, through 127.  In other words, the code
934       points from 0 to 127 are all in the "Basic Latin" block.  Similarly,
935       all code points in the range from 0x0080 up to (but not including)
936       0x0100 are in the block named "Latin-1 Supplement", etc.  (Notice that
937       the return is the old-style block names; see "Old-style versus new-
938       style block names").
939
940       The final line (with Index [242]) means that the value for all code
941       points above the legal Unicode maximum code point have the value
942       "No_Block", which is the term Unicode uses for a non-existing block.
943
944       The arrays completely specify the mappings for all possible code
945       points.  The final element in an inversion map returned by this
946       function will always be for the range that consists of all the code
947       points that aren't legal Unicode, but that are expressible on the
948       platform.  (That is, it starts with code point 0x110000, the first code
949       point above the legal Unicode maximum, and extends to infinity.) The
950       value for that range will be the same that any typical unassigned code
951       point has for the specified property.  (Certain unassigned code points
952       are not "typical"; for example the non-character code points, or those
953       in blocks that are to be written right-to-left.  The above-Unicode
954       range's value is not based on these atypical code points.)  It could be
955       argued that, instead of treating these as unassigned Unicode code
956       points, the value for this range should be "undef".  If you wish, you
957       can change the returned arrays accordingly.
958
959       The maps are almost always simple scalars that should be interpreted
960       as-is.  These values are those given in the Unicode-supplied data
961       files, which may be inconsistent as to capitalization and as to which
962       synonym for a property-value is given.  The results may be normalized
963       by using the "prop_value_aliases()" function.
964
965       There are exceptions to the simple scalar maps.  Some properties have
966       some elements in their map list that are themselves lists of scalars;
967       and some special strings are returned that are not to be interpreted
968       as-is.  Element [2] (placed into $format in the example above) of the
969       returned four element list tells you if the map has any of these
970       special elements or not, as follows:
971
972       "s" means all the elements of the map array are simple scalars, with no
973           special elements.  Almost all properties are like this, like the
974           "block" example above.
975
976       "sl"
977           means that some of the map array elements have the form given by
978           "s", and the rest are lists of scalars.  For example, here is a
979           portion of the output of calling "prop_invmap"() with the "Script
980           Extensions" property:
981
982            @scripts_ranges  @scripts_maps
983                 ...
984                 0x0953      Devanagari
985                 0x0964      [ Bengali, Devanagari, Gurumukhi, Oriya ]
986                 0x0966      Devanagari
987                 0x0970      Common
988
989           Here, the code points 0x964 and 0x965 are both used in Bengali,
990           Devanagari, Gurmukhi, and Oriya, but no other scripts.
991
992           The Name_Alias property is also of this form.  But each scalar
993           consists of two components:  1) the name, and 2) the type of alias
994           this is.  They are separated by a colon and a space.  In Unicode
995           6.1, there are several alias types:
996
997           "correction"
998               indicates that the name is a corrected form for the original
999               name (which remains valid) for the same code point.
1000
1001           "control"
1002               adds a new name for a control character.
1003
1004           "alternate"
1005               is an alternate name for a character
1006
1007           "figment"
1008               is a name for a character that has been documented but was
1009               never in any actual standard.
1010
1011           "abbreviation"
1012               is a common abbreviation for a character
1013
1014           The lists are ordered (roughly) so the most preferred names come
1015           before less preferred ones.
1016
1017           For example,
1018
1019            @aliases_ranges        @alias_maps
1020               ...
1021               0x009E        [ 'PRIVACY MESSAGE: control', 'PM: abbreviation' ]
1022               0x009F        [ 'APPLICATION PROGRAM COMMAND: control',
1023                               'APC: abbreviation'
1024                             ]
1025               0x00A0        'NBSP: abbreviation'
1026               0x00A1        ""
1027               0x00AD        'SHY: abbreviation'
1028               0x00AE        ""
1029               0x01A2        'LATIN CAPITAL LETTER GHA: correction'
1030               0x01A3        'LATIN SMALL LETTER GHA: correction'
1031               0x01A4        ""
1032               ...
1033
1034           A map to the empty string means that there is no alias defined for
1035           the code point.
1036
1037       "a" is like "s" in that all the map array elements are scalars, but
1038           here they are restricted to all being integers, and some have to be
1039           adjusted (hence the name "a") to get the correct result.  For
1040           example, in:
1041
1042            my ($uppers_ranges_ref, $uppers_maps_ref, $format)
1043                                     = prop_invmap("Simple_Uppercase_Mapping");
1044
1045           the returned arrays look like this:
1046
1047            @$uppers_ranges_ref    @$uppers_maps_ref   Note
1048                  0                      0
1049                 97                     65          'a' maps to 'A', b => B ...
1050                123                      0
1051                181                    924          MICRO SIGN => Greek Cap MU
1052                182                      0
1053                ...
1054
1055           Let's start with the second line.  It says that the uppercase of
1056           code point 97 is 65; or "uc("a")" == "A".  But the line is for the
1057           entire range of code points 97 through 122.  To get the mapping for
1058           any code point in a range, you take the offset it has from the
1059           beginning code point of the range, and add that to the mapping for
1060           that first code point.  So, the mapping for 122 ("z") is derived by
1061           taking the offset of 122 from 97 (=25) and adding that to 65,
1062           yielding 90 ("z").  Likewise for everything in between.
1063
1064           The first line works the same way.  The first map in a range is
1065           always the correct value for its code point (because the adjustment
1066           is 0).  Thus the "uc(chr(0))" is just itself.  Also, "uc(chr(1))"
1067           is also itself, as the adjustment is 0+1-0 .. "uc(chr(96))" is 96.
1068
1069           Requiring this simple adjustment allows the returned arrays to be
1070           significantly smaller than otherwise, up to a factor of 10,
1071           speeding up searching through them.
1072
1073       "al"
1074           means that some of the map array elements have the form given by
1075           "a", and the rest are ordered lists of code points.  For example,
1076           in:
1077
1078            my ($uppers_ranges_ref, $uppers_maps_ref, $format)
1079                                            = prop_invmap("Uppercase_Mapping");
1080
1081           the returned arrays look like this:
1082
1083            @$uppers_ranges_ref    @$uppers_maps_ref
1084                  0                      0
1085                 97                     65
1086                123                      0
1087                181                    924
1088                182                      0
1089                ...
1090               0x0149              [ 0x02BC 0x004E ]
1091               0x014A                    0
1092               0x014B                  330
1093                ...
1094
1095           This is the full Uppercase_Mapping property (as opposed to the
1096           Simple_Uppercase_Mapping given in the example for format "a").  The
1097           only difference between the two in the ranges shown is that the
1098           code point at 0x0149 (LATIN SMALL LETTER N PRECEDED BY APOSTROPHE)
1099           maps to a string of two characters, 0x02BC (MODIFIER LETTER
1100           APOSTROPHE) followed by 0x004E (LATIN CAPITAL LETTER N).
1101
1102           No adjustments are needed to entries that are references to arrays;
1103           each such entry will have exactly one element in its range, so the
1104           offset is always 0.
1105
1106       "ae"
1107           This is like "a", but some elements are the empty string, and
1108           should not be adjusted.  The one internal Perl property accessible
1109           by "prop_invmap" is of this type: "Perl_Decimal_Digit" returns an
1110           inversion map which gives the numeric values that are represented
1111           by the Unicode decimal digit characters.  Characters that don't
1112           represent decimal digits map to the empty string, like so:
1113
1114            @digits    @values
1115            0x0000       ""
1116            0x0030        0
1117            0x003A:      ""
1118            0x0660:       0
1119            0x066A:      ""
1120            0x06F0:       0
1121            0x06FA:      ""
1122            0x07C0:       0
1123            0x07CA:      ""
1124            0x0966:       0
1125            ...
1126
1127           This means that the code points from 0 to 0x2F do not represent
1128           decimal digits; the code point 0x30 (DIGIT ZERO) represents 0;
1129           code point 0x31, (DIGIT ONE), represents 0+1-0 = 1; ... code point
1130           0x39, (DIGIT NINE), represents 0+9-0 = 9; ... code points 0x3A
1131           through 0x65F do not represent decimal digits; 0x660 (ARABIC-INDIC
1132           DIGIT ZERO), represents 0; ... 0x07C1 (NKO DIGIT ONE), represents
1133           0+1-0 = 1 ...
1134
1135       "ale"
1136           is a combination of the "al" type and the "ae" type.  Some of the
1137           map array elements have the forms given by "al", and the rest are
1138           the empty string.  The property "NFKC_Casefold" has this form.  An
1139           example slice is:
1140
1141            @$ranges_ref  @$maps_ref         Note
1142               ...
1143              0x00AA       97                FEMININE ORDINAL INDICATOR => 'a'
1144              0x00AB        0
1145              0x00AD                         SOFT HYPHEN => ""
1146              0x00AE        0
1147              0x00AF     [ 0x0020, 0x0304 ]  MACRON => SPACE . COMBINING MACRON
1148              0x00B0        0
1149              ...
1150
1151       "ar"
1152           means that all the elements of the map array are either rational
1153           numbers or the string "NaN", meaning "Not a Number".  A rational
1154           number is either an integer, or two integers separated by a solidus
1155           ("/").  The second integer represents the denominator of the
1156           division implied by the solidus, and is actually always positive,
1157           so it is guaranteed not to be 0 and to not to be signed.  When the
1158           element is a plain integer (without the solidus), it may need to be
1159           adjusted to get the correct value by adding the offset, just as
1160           other "a" properties.  No adjustment is needed for fractions, as
1161           the range is guaranteed to have just a single element, and so the
1162           offset is always 0.
1163
1164           If you want to convert the returned map to entirely scalar numbers,
1165           you can use something like this:
1166
1167            my ($invlist_ref, $invmap_ref, $format) = prop_invmap($property);
1168            if ($format && $format eq "ar") {
1169                map { $_ = eval $_ } @$invmap_ref;
1170            }
1171
1172           Here's some entries from the output of the property "Nv", which has
1173           format "ar".
1174
1175            @numerics_ranges  @numerics_maps       Note
1176                   0x00           "NaN"
1177                   0x30             0           DIGIT 0 .. DIGIT 9
1178                   0x3A           "NaN"
1179                   0xB2             2           SUPERSCRIPTs 2 and 3
1180                   0xB4           "NaN"
1181                   0xB9             1           SUPERSCRIPT 1
1182                   0xBA           "NaN"
1183                   0xBC            1/4          VULGAR FRACTION 1/4
1184                   0xBD            1/2          VULGAR FRACTION 1/2
1185                   0xBE            3/4          VULGAR FRACTION 3/4
1186                   0xBF           "NaN"
1187                   0x660            0           ARABIC-INDIC DIGIT ZERO .. NINE
1188                   0x66A          "NaN"
1189
1190       "n" means the Name property.  All the elements of the map array are
1191           simple scalars, but some of them contain special strings that
1192           require more work to get the actual name.
1193
1194           Entries such as:
1195
1196            CJK UNIFIED IDEOGRAPH-<code point>
1197
1198           mean that the name for the code point is "CJK UNIFIED IDEOGRAPH-"
1199           with the code point (expressed in hexadecimal) appended to it, like
1200           "CJK UNIFIED IDEOGRAPH-3403" (similarly for
1201           "CJK COMPATIBILITY IDEOGRAPH-<code point>").
1202
1203           Also, entries like
1204
1205            <hangul syllable>
1206
1207           means that the name is algorithmically calculated.  This is easily
1208           done by the function "charnames::viacode(code)" in charnames.
1209
1210           Note that for control characters ("Gc=cc"), Unicode's data files
1211           have the string ""<control>"", but the real name of each of these
1212           characters is the empty string.  This function returns that real
1213           name, the empty string.  (There are names for these characters, but
1214           they are considered aliases, not the Name property name, and are
1215           contained in the "Name_Alias" property.)
1216
1217       "ad"
1218           means the Decomposition_Mapping property.  This property is like
1219           "al" properties, except that one of the scalar elements is of the
1220           form:
1221
1222            <hangul syllable>
1223
1224           This signifies that this entry should be replaced by the
1225           decompositions for all the code points whose decomposition is
1226           algorithmically calculated.  (All of them are currently in one
1227           range and no others outisde the range are likely to ever be added
1228           to Unicode; the "n" format has this same entry.)  These can be
1229           generated via the function Unicode::Normalize::NFD().
1230
1231           Note that the mapping is the one that is specified in the Unicode
1232           data files, and to get the final decomposition, it may need to be
1233           applied recursively.
1234
1235       Note that a format begins with the letter "a" if and only the property
1236       it is for requires adjustments by adding the offsets in multi-element
1237       ranges.  For all these properties, an entry should be adjusted only if
1238       the map is a scalar which is an integer.  That is, it must match the
1239       regular expression:
1240
1241           / ^ -? \d+ $ /xa
1242
1243       Further, the first element in a range never needs adjustment, as the
1244       adjustment would be just adding 0.
1245
1246       A binary search can be used to quickly find a code point in the
1247       inversion list, and hence its corresponding mapping.
1248
1249       The final element (index [3], assigned to $default in the "block"
1250       example) in the four element list returned by this function may be
1251       useful for applications that wish to convert the returned inversion map
1252       data structure into some other, such as a hash.  It gives the mapping
1253       that most code points map to under the property.  If you establish the
1254       convention that any code point not explicitly listed in your data
1255       structure maps to this value, you can potentially make your data
1256       structure much smaller.  As you construct your data structure from the
1257       one returned by this function, simply ignore those ranges that map to
1258       this value, generally called the "default" value.  For example, to
1259       convert to the data structure searchable by "charinrange()", you can
1260       follow this recipe for properties that don't require adjustments:
1261
1262        my ($list_ref, $map_ref, $format, $missing) = prop_invmap($property);
1263        my @range_list;
1264
1265        # Look at each element in the list, but the -2 is needed because we
1266        # look at $i+1 in the loop, and the final element is guaranteed to map
1267        # to $missing by prop_invmap(), so we would skip it anyway.
1268        for my $i (0 .. @$list_ref - 2) {
1269           next if $map_ref->[$i] eq $missing;
1270           push @range_list, [ $list_ref->[$i],
1271                               $list_ref->[$i+1],
1272                               $map_ref->[$i]
1273                             ];
1274        }
1275
1276        print charinrange(\@range_list, $code_point), "\n";
1277
1278       With this, "charinrange()" will return "undef" if its input code point
1279       maps to $missing.  You can avoid this by omitting the "next" statement,
1280       and adding a line after the loop to handle the final element of the
1281       inversion map.
1282
1283       Similarly, this recipe can be used for properties that do require
1284       adjustments:
1285
1286        for my $i (0 .. @$list_ref - 2) {
1287           next if $map_ref->[$i] eq $missing;
1288
1289           # prop_invmap() guarantees that if the mapping is to an array, the
1290           # range has just one element, so no need to worry about adjustments.
1291           if (ref $map_ref->[$i]) {
1292               push @range_list,
1293                          [ $list_ref->[$i], $list_ref->[$i], $map_ref->[$i] ];
1294           }
1295           else {  # Otherwise each element is actually mapped to a separate
1296                   # value, so the range has to be split into single code point
1297                   # ranges.
1298
1299               my $adjustment = 0;
1300
1301               # For each code point that gets mapped to something...
1302               for my $j ($list_ref->[$i] .. $list_ref->[$i+1] -1 ) {
1303
1304                   # ... add a range consisting of just it mapping to the
1305                   # original plus the adjustment, which is incremented for the
1306                   # next time through the loop, as the offset increases by 1
1307                   # for each element in the range
1308                   push @range_list,
1309                                    [ $j, $j, $map_ref->[$i] + $adjustment++ ];
1310               }
1311           }
1312        }
1313
1314       Note that the inversion maps returned for the "Case_Folding" and
1315       "Simple_Case_Folding" properties do not include the Turkic-locale
1316       mappings.  Use "casefold()" for these.
1317
1318       "prop_invmap" does not know about any user-defined properties, and will
1319       return "undef" if called with one of those.
1320
1321   Unicode::UCD::UnicodeVersion
1322       This returns the version of the Unicode Character Database, in other
1323       words, the version of the Unicode standard the database implements.
1324       The version is a string of numbers delimited by dots ('.').
1325
1326   Blocks versus Scripts
1327       The difference between a block and a script is that scripts are closer
1328       to the linguistic notion of a set of code points required to present
1329       languages, while block is more of an artifact of the Unicode code point
1330       numbering and separation into blocks of (mostly) 256 code points.
1331
1332       For example the Latin script is spread over several blocks, such as
1333       "Basic Latin", "Latin 1 Supplement", "Latin Extended-A", and "Latin
1334       Extended-B".  On the other hand, the Latin script does not contain all
1335       the characters of the "Basic Latin" block (also known as ASCII): it
1336       includes only the letters, and not, for example, the digits or the
1337       punctuation.
1338
1339       For blocks see <http://www.unicode.org/Public/UNIDATA/Blocks.txt>
1340
1341       For scripts see UTR #24: <http://www.unicode.org/unicode/reports/tr24/>
1342
1343   Matching Scripts and Blocks
1344       Scripts are matched with the regular-expression construct "\p{...}"
1345       (e.g. "\p{Tibetan}" matches characters of the Tibetan script), while
1346       "\p{Blk=...}" is used for blocks (e.g. "\p{Blk=Tibetan}" matches any of
1347       the 256 code points in the Tibetan block).
1348
1349   Old-style versus new-style block names
1350       Unicode publishes the names of blocks in two different styles, though
1351       the two are equivalent under Unicode's loose matching rules.
1352
1353       The original style uses blanks and hyphens in the block names (except
1354       for "No_Block"), like so:
1355
1356        Miscellaneous Mathematical Symbols-B
1357
1358       The newer style replaces these with underscores, like this:
1359
1360        Miscellaneous_Mathematical_Symbols_B
1361
1362       This newer style is consistent with the values of other Unicode
1363       properties.  To preserve backward compatibility, all the functions in
1364       Unicode::UCD that return block names (except one) return the old-style
1365       ones.  That one function, "prop_value_aliases()" can be used to convert
1366       from old-style to new-style:
1367
1368        my $new_style = prop_values_aliases("block", $old_style);
1369
1370       Perl also has single-form extensions that refer to blocks,
1371       "In_Cyrillic", meaning "Block=Cyrillic".  These have always been
1372       written in the new style.
1373
1374       To convert from new-style to old-style, follow this recipe:
1375
1376        $old_style = charblock((prop_invlist("block=$new_style"))[0]);
1377
1378       (which finds the range of code points in the block using
1379       "prop_invlist", gets the lower end of the range (0th element) and then
1380       looks up the old name for its block using "charblock").
1381
1382       Note that starting in Unicode 6.1, many of the block names have shorter
1383       synonyms.  These are always given in the new style.
1384

BUGS

1386       Does not yet support EBCDIC platforms.
1387

AUTHOR

1389       Jarkko Hietaniemi.  Now maintained by perl5 porters.
1390
1391
1392
1393perl v5.16.3                      2013-03-04                 Unicode::UCD(3pm)
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