source: for-distributions/trunk/bin/windows/perl/lib/charnames.pm@ 14489

Last change on this file since 14489 was 14489, checked in by oranfry, 17 years ago

upgrading to perl 5.8

File size: 15.1 KB
Line 
1package charnames;
2use strict;
3use warnings;
4use Carp;
5use File::Spec;
6our $VERSION = '1.05';
7
8use bytes (); # for $bytes::hint_bits
9$charnames::hint_bits = 0x20000; # HINT_LOCALIZE_HH
10
11my %alias1 = (
12 # Icky 3.2 names with parentheses.
13 'LINE FEED' => 'LINE FEED (LF)',
14 'FORM FEED' => 'FORM FEED (FF)',
15 'CARRIAGE RETURN' => 'CARRIAGE RETURN (CR)',
16 'NEXT LINE' => 'NEXT LINE (NEL)',
17 # Convenience.
18 'LF' => 'LINE FEED (LF)',
19 'FF' => 'FORM FEED (FF)',
20 'CR' => 'CARRIAGE RETURN (CR)',
21 'NEL' => 'NEXT LINE (NEL)',
22 # More convenience. For futher convencience,
23 # it is suggested some way using using the NamesList
24 # aliases is implemented.
25 'ZWNJ' => 'ZERO WIDTH NON-JOINER',
26 'ZWJ' => 'ZERO WIDTH JOINER',
27 'BOM' => 'BYTE ORDER MARK',
28 );
29
30my %alias2 = (
31 # Pre-3.2 compatibility (only for the first 256 characters).
32 'HORIZONTAL TABULATION' => 'CHARACTER TABULATION',
33 'VERTICAL TABULATION' => 'LINE TABULATION',
34 'FILE SEPARATOR' => 'INFORMATION SEPARATOR FOUR',
35 'GROUP SEPARATOR' => 'INFORMATION SEPARATOR THREE',
36 'RECORD SEPARATOR' => 'INFORMATION SEPARATOR TWO',
37 'UNIT SEPARATOR' => 'INFORMATION SEPARATOR ONE',
38 'PARTIAL LINE DOWN' => 'PARTIAL LINE FORWARD',
39 'PARTIAL LINE UP' => 'PARTIAL LINE BACKWARD',
40 );
41
42my %alias3 = (
43 # User defined aliasses. Even more convenient :)
44 );
45my $txt;
46
47sub alias (@)
48{
49 @_ or return %alias3;
50 my $alias = ref $_[0] ? $_[0] : { @_ };
51 @alias3{keys %$alias} = values %$alias;
52} # alias
53
54sub alias_file ($)
55{
56 my ($arg, $file) = @_;
57 if (-f $arg && File::Spec->file_name_is_absolute ($arg)) {
58 $file = $arg;
59 }
60 elsif ($arg =~ m/^\w+$/) {
61 $file = "unicore/${arg}_alias.pl";
62 }
63 else {
64 croak "Charnames alias files can only have identifier characters";
65 }
66 if (my @alias = do $file) {
67 @alias == 1 && !defined $alias[0] and
68 croak "$file cannot be used as alias file for charnames";
69 @alias % 2 and
70 croak "$file did not return a (valid) list of alias pairs";
71 alias (@alias);
72 return (1);
73 }
74 0;
75} # alias_file
76
77# This is not optimized in any way yet
78sub charnames
79{
80 my $name = shift;
81
82 if (exists $alias1{$name}) {
83 $name = $alias1{$name};
84 }
85 elsif (exists $alias2{$name}) {
86 require warnings;
87 warnings::warnif('deprecated', qq{Unicode character name "$name" is deprecated, use "$alias2{$name}" instead});
88 $name = $alias2{$name};
89 }
90 elsif (exists $alias3{$name}) {
91 $name = $alias3{$name};
92 }
93
94 my $ord;
95 my @off;
96 my $fname;
97
98 if ($name eq "BYTE ORDER MARK") {
99 $fname = $name;
100 $ord = 0xFEFF;
101 } else {
102 ## Suck in the code/name list as a big string.
103 ## Lines look like:
104 ## "0052\t\tLATIN CAPITAL LETTER R\n"
105 $txt = do "unicore/Name.pl" unless $txt;
106
107 ## @off will hold the index into the code/name string of the start and
108 ## end of the name as we find it.
109
110 ## If :full, look for the name exactly
111 if ($^H{charnames_full} and $txt =~ /\t\t\Q$name\E$/m) {
112 @off = ($-[0], $+[0]);
113 }
114
115 ## If we didn't get above, and :short allowed, look for the short name.
116 ## The short name is like "greek:Sigma"
117 unless (@off) {
118 if ($^H{charnames_short} and $name =~ /^(.+?):(.+)/s) {
119 my ($script, $cname) = ($1, $2);
120 my $case = $cname =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL";
121 if ($txt =~ m/\t\t\U$script\E (?:$case )?LETTER \U\Q$cname\E$/m) {
122 @off = ($-[0], $+[0]);
123 }
124 }
125 }
126
127 ## If we still don't have it, check for the name among the loaded
128 ## scripts.
129 if (not @off) {
130 my $case = $name =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL";
131 for my $script (@{$^H{charnames_scripts}}) {
132 if ($txt =~ m/\t\t$script (?:$case )?LETTER \U\Q$name\E$/m) {
133 @off = ($-[0], $+[0]);
134 last;
135 }
136 }
137 }
138
139 ## If we don't have it by now, give up.
140 unless (@off) {
141 carp "Unknown charname '$name'";
142 return "\x{FFFD}";
143 }
144
145 ##
146 ## Now know where in the string the name starts.
147 ## The code, in hex, is before that.
148 ##
149 ## The code can be 4-6 characters long, so we've got to sort of
150 ## go look for it, just after the newline that comes before $off[0].
151 ##
152 ## This would be much easier if unicore/Name.pl had info in
153 ## a name/code order, instead of code/name order.
154 ##
155 ## The +1 after the rindex() is to skip past the newline we're finding,
156 ## or, if the rindex() fails, to put us to an offset of zero.
157 ##
158 my $hexstart = rindex($txt, "\n", $off[0]) + 1;
159
160 ## we know where it starts, so turn into number -
161 ## the ordinal for the char.
162 $ord = hex substr($txt, $hexstart, $off[0] - $hexstart);
163 }
164
165 if ($^H & $bytes::hint_bits) { # "use bytes" in effect?
166 use bytes;
167 return chr $ord if $ord <= 255;
168 my $hex = sprintf "%04x", $ord;
169 if (not defined $fname) {
170 $fname = substr $txt, $off[0] + 2, $off[1] - $off[0] - 2;
171 }
172 croak "Character 0x$hex with name '$fname' is above 0xFF";
173 }
174
175 no warnings 'utf8'; # allow even illegal characters
176 return pack "U", $ord;
177} # charnames
178
179sub import
180{
181 shift; ## ignore class name
182
183 if (not @_) {
184 carp("`use charnames' needs explicit imports list");
185 }
186 $^H |= $charnames::hint_bits;
187 $^H{charnames} = \&charnames ;
188
189 ##
190 ## fill %h keys with our @_ args.
191 ##
192 my ($promote, %h, @args) = (0);
193 while (my $arg = shift) {
194 if ($arg eq ":alias") {
195 @_ or
196 croak ":alias needs an argument in charnames";
197 my $alias = shift;
198 if (ref $alias) {
199 ref $alias eq "HASH" or
200 croak "Only HASH reference supported as argument to :alias";
201 alias ($alias);
202 next;
203 }
204 if ($alias =~ m{:(\w+)$}) {
205 $1 eq "full" || $1 eq "short" and
206 croak ":alias cannot use existing pragma :$1 (reversed order?)";
207 alias_file ($1) and $promote = 1;
208 next;
209 }
210 alias_file ($alias);
211 next;
212 }
213 if (substr($arg, 0, 1) eq ':' and ! ($arg eq ":full" || $arg eq ":short")) {
214 warn "unsupported special '$arg' in charnames";
215 next;
216 }
217 push @args, $arg;
218 }
219 @args == 0 && $promote and @args = (":full");
220 @h{@args} = (1) x @args;
221
222 $^H{charnames_full} = delete $h{':full'};
223 $^H{charnames_short} = delete $h{':short'};
224 $^H{charnames_scripts} = [map uc, keys %h];
225
226 ##
227 ## If utf8? warnings are enabled, and some scripts were given,
228 ## see if at least we can find one letter of each script.
229 ##
230 if (warnings::enabled('utf8') && @{$^H{charnames_scripts}}) {
231 $txt = do "unicore/Name.pl" unless $txt;
232
233 for my $script (@{$^H{charnames_scripts}}) {
234 if (not $txt =~ m/\t\t$script (?:CAPITAL |SMALL )?LETTER /) {
235 warnings::warn('utf8', "No such script: '$script'");
236 }
237 }
238 }
239} # import
240
241my %viacode;
242
243sub viacode
244{
245 if (@_ != 1) {
246 carp "charnames::viacode() expects one argument";
247 return;
248 }
249
250 my $arg = shift;
251
252 # this comes actually from Unicode::UCD, where it is the named
253 # function _getcode (), but it avoids the overhead of loading it
254 my $hex;
255 if ($arg =~ /^[1-9]\d*$/) {
256 $hex = sprintf "%04X", $arg;
257 } elsif ($arg =~ /^(?:[Uu]\+|0[xX])?([[:xdigit:]]+)$/) {
258 $hex = $1;
259 } else {
260 carp("unexpected arg \"$arg\" to charnames::viacode()");
261 return;
262 }
263
264 # checking the length first is slightly faster
265 if (length($hex) > 5 && hex($hex) > 0x10FFFF) {
266 carp sprintf "Unicode characters only allocated up to U+10FFFF (you asked for U+%X)", $hex;
267 return;
268 }
269
270 return $viacode{$hex} if exists $viacode{$hex};
271
272 $txt = do "unicore/Name.pl" unless $txt;
273
274 return unless $txt =~ m/^$hex\t\t(.+)/m;
275
276 $viacode{$hex} = $1;
277} # viacode
278
279my %vianame;
280
281sub vianame
282{
283 if (@_ != 1) {
284 carp "charnames::vianame() expects one name argument";
285 return ()
286 }
287
288 my $arg = shift;
289
290 return chr hex $1 if $arg =~ /^U\+([0-9a-fA-F]+)$/;
291
292 return $vianame{$arg} if exists $vianame{$arg};
293
294 $txt = do "unicore/Name.pl" unless $txt;
295
296 my $pos = index $txt, "\t\t$arg\n";
297 if ($[ <= $pos) {
298 my $posLF = rindex $txt, "\n", $pos;
299 (my $code = substr $txt, $posLF + 1, 6) =~ tr/\t//d;
300 return $vianame{$arg} = hex $code;
301
302 # If $pos is at the 1st line, $posLF must be $[ - 1 (not found);
303 # then $posLF + 1 equals to $[ (at the beginning of $txt).
304 # Otherwise $posLF is the position of "\n";
305 # then $posLF + 1 must be the position of the next to "\n"
306 # (the beginning of the line).
307 # substr($txt, $posLF + 1, 6) may be "0000\t\t", "00A1\t\t",
308 # "10300\t", "100000", etc. So we can get the code via removing TAB.
309 } else {
310 return;
311 }
312} # vianame
313
314
3151;
316__END__
317
318=head1 NAME
319
320charnames - define character names for C<\N{named}> string literal escapes
321
322=head1 SYNOPSIS
323
324 use charnames ':full';
325 print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";
326
327 use charnames ':short';
328 print "\N{greek:Sigma} is an upper-case sigma.\n";
329
330 use charnames qw(cyrillic greek);
331 print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";
332
333 use charnames ":full", ":alias" => {
334 e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
335 };
336 print "\N{e_ACUTE} is a small letter e with an acute.\n";
337
338 use charnames ();
339 print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
340 printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"
341
342=head1 DESCRIPTION
343
344Pragma C<use charnames> supports arguments C<:full>, C<:short>, script
345names and customized aliases. If C<:full> is present, for expansion of
346C<\N{CHARNAME}>, the string C<CHARNAME> is first looked up in the list of
347standard Unicode character names. If C<:short> is present, and
348C<CHARNAME> has the form C<SCRIPT:CNAME>, then C<CNAME> is looked up
349as a letter in script C<SCRIPT>. If pragma C<use charnames> is used
350with script name arguments, then for C<\N{CHARNAME}> the name
351C<CHARNAME> is looked up as a letter in the given scripts (in the
352specified order). Customized aliases are explained in L</CUSTOM ALIASES>.
353
354For lookup of C<CHARNAME> inside a given script C<SCRIPTNAME>
355this pragma looks for the names
356
357 SCRIPTNAME CAPITAL LETTER CHARNAME
358 SCRIPTNAME SMALL LETTER CHARNAME
359 SCRIPTNAME LETTER CHARNAME
360
361in the table of standard Unicode names. If C<CHARNAME> is lowercase,
362then the C<CAPITAL> variant is ignored, otherwise the C<SMALL> variant
363is ignored.
364
365Note that C<\N{...}> is compile-time, it's a special form of string
366constant used inside double-quoted strings: in other words, you cannot
367use variables inside the C<\N{...}>. If you want similar run-time
368functionality, use charnames::vianame().
369
370For the C0 and C1 control characters (U+0000..U+001F, U+0080..U+009F)
371as of Unicode 3.1, there are no official Unicode names but you can use
372instead the ISO 6429 names (LINE FEED, ESCAPE, and so forth). In
373Unicode 3.2 (as of Perl 5.8) some naming changes take place ISO 6429
374has been updated, see L</ALIASES>. Also note that the U+UU80, U+0081,
375U+0084, and U+0099 do not have names even in ISO 6429.
376
377Since the Unicode standard uses "U+HHHH", so can you: "\N{U+263a}"
378is the Unicode smiley face, or "\N{WHITE SMILING FACE}".
379
380=head1 CUSTOM TRANSLATORS
381
382The mechanism of translation of C<\N{...}> escapes is general and not
383hardwired into F<charnames.pm>. A module can install custom
384translations (inside the scope which C<use>s the module) with the
385following magic incantation:
386
387 use charnames (); # for $charnames::hint_bits
388 sub import {
389 shift;
390 $^H |= $charnames::hint_bits;
391 $^H{charnames} = \&translator;
392 }
393
394Here translator() is a subroutine which takes C<CHARNAME> as an
395argument, and returns text to insert into the string instead of the
396C<\N{CHARNAME}> escape. Since the text to insert should be different
397in C<bytes> mode and out of it, the function should check the current
398state of C<bytes>-flag as in:
399
400 use bytes (); # for $bytes::hint_bits
401 sub translator {
402 if ($^H & $bytes::hint_bits) {
403 return bytes_translator(@_);
404 }
405 else {
406 return utf8_translator(@_);
407 }
408 }
409
410=head1 CUSTOM ALIASES
411
412This version of charnames supports three mechanisms of adding local
413or customized aliases to standard Unicode naming conventions (:full)
414
415=head2 Anonymous hashes
416
417 use charnames ":full", ":alias" => {
418 e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
419 };
420 my $str = "\N{e_ACUTE}";
421
422=head2 Alias file
423
424 use charnames ":full", ":alias" => "pro";
425
426 will try to read "unicore/pro_alias.pl" from the @INC path. This
427 file should return a list in plain perl:
428
429 (
430 A_GRAVE => "LATIN CAPITAL LETTER A WITH GRAVE",
431 A_CIRCUM => "LATIN CAPITAL LETTER A WITH CIRCUMFLEX",
432 A_DIAERES => "LATIN CAPITAL LETTER A WITH DIAERESIS",
433 A_TILDE => "LATIN CAPITAL LETTER A WITH TILDE",
434 A_BREVE => "LATIN CAPITAL LETTER A WITH BREVE",
435 A_RING => "LATIN CAPITAL LETTER A WITH RING ABOVE",
436 A_MACRON => "LATIN CAPITAL LETTER A WITH MACRON",
437 );
438
439=head2 Alias shortcut
440
441 use charnames ":alias" => ":pro";
442
443 works exactly the same as the alias pairs, only this time,
444 ":full" is inserted automatically as first argument (if no
445 other argument is given).
446
447=head1 charnames::viacode(code)
448
449Returns the full name of the character indicated by the numeric code.
450The example
451
452 print charnames::viacode(0x2722);
453
454prints "FOUR TEARDROP-SPOKED ASTERISK".
455
456Returns undef if no name is known for the code.
457
458This works only for the standard names, and does not yet apply
459to custom translators.
460
461Notice that the name returned for of U+FEFF is "ZERO WIDTH NO-BREAK
462SPACE", not "BYTE ORDER MARK".
463
464=head1 charnames::vianame(name)
465
466Returns the code point indicated by the name.
467The example
468
469 printf "%04X", charnames::vianame("FOUR TEARDROP-SPOKED ASTERISK");
470
471prints "2722".
472
473Returns undef if the name is unknown.
474
475This works only for the standard names, and does not yet apply
476to custom translators.
477
478=head1 ALIASES
479
480A few aliases have been defined for convenience: instead of having
481to use the official names
482
483 LINE FEED (LF)
484 FORM FEED (FF)
485 CARRIAGE RETURN (CR)
486 NEXT LINE (NEL)
487
488(yes, with parentheses) one can use
489
490 LINE FEED
491 FORM FEED
492 CARRIAGE RETURN
493 NEXT LINE
494 LF
495 FF
496 CR
497 NEL
498
499One can also use
500
501 BYTE ORDER MARK
502 BOM
503
504and
505
506 ZWNJ
507 ZWJ
508
509for ZERO WIDTH NON-JOINER and ZERO WIDTH JOINER.
510
511For backward compatibility one can use the old names for
512certain C0 and C1 controls
513
514 old new
515
516 HORIZONTAL TABULATION CHARACTER TABULATION
517 VERTICAL TABULATION LINE TABULATION
518 FILE SEPARATOR INFORMATION SEPARATOR FOUR
519 GROUP SEPARATOR INFORMATION SEPARATOR THREE
520 RECORD SEPARATOR INFORMATION SEPARATOR TWO
521 UNIT SEPARATOR INFORMATION SEPARATOR ONE
522 PARTIAL LINE DOWN PARTIAL LINE FORWARD
523 PARTIAL LINE UP PARTIAL LINE BACKWARD
524
525but the old names in addition to giving the character
526will also give a warning about being deprecated.
527
528=head1 ILLEGAL CHARACTERS
529
530If you ask by name for a character that does not exist, a warning is
531given and the Unicode I<replacement character> "\x{FFFD}" is returned.
532
533If you ask by code for a character that does not exist, no warning is
534given and C<undef> is returned. (Though if you ask for a code point
535past U+10FFFF you do get a warning.)
536
537=head1 BUGS
538
539Since evaluation of the translation function happens in a middle of
540compilation (of a string literal), the translation function should not
541do any C<eval>s or C<require>s. This restriction should be lifted in
542a future version of Perl.
543
544=cut
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