xref: /openbsd-src/gnu/usr.bin/perl/lib/_charnames.pm (revision f2da64fbbbf1b03f09f390ab01267c93dfd77c4c)
1# !!!!!!!   INTERNAL PERL USE ONLY   !!!!!!!
2# This helper module is for internal use by core Perl only.  This module is
3# subject to change or removal at any time without notice.  Don't use it
4# directly.  Use the public <charnames> module instead.
5
6package _charnames;
7use strict;
8use warnings;
9use File::Spec;
10our $VERSION = '1.39';
11use unicore::Name;    # mktables-generated algorithmically-defined names
12
13use bytes ();          # for $bytes::hint_bits
14use re "/aa";          # Everything in here should be ASCII
15
16$Carp::Internal{ (__PACKAGE__) } = 1;
17
18# Translate between Unicode character names and their code points.  This is a
19# submodule of package <charnames>, used to allow \N{...} to be autoloaded,
20# but it was decided not to autoload the various functions in charnames; the
21# splitting allows this behavior.
22#
23# The official names with their code points are stored in a table in
24# lib/unicore/Name.pl which is read in as a large string (almost 3/4 Mb in
25# Unicode 6.0).  Each code point/name combination is separated by a \n in the
26# string.  (Some of the CJK and the Hangul syllable names are determined
27# instead algorithmically via subroutines stored instead in
28# lib/unicore/Name.pm).  Because of the large size of this table, it isn't
29# converted into hashes for faster lookup.
30#
31# But, user defined aliases are stored in their own hashes, as are Perl
32# extensions to the official names.  These are checked first before looking at
33# the official table.
34#
35# Basically, the table is grepped for the input code point (viacode()) or
36# name (the other functions), and the corresponding value on the same line is
37# returned.  The grepping is done by turning the input into a regular
38# expression.  Thus, the same table does double duty, used by both name and
39# code point lookup.  (If we were to have hashes, we would need two, one for
40# each lookup direction.)
41#
42# For loose name matching, the logical thing would be to have a table
43# with all the ignorable characters squeezed out, and then grep it with the
44# similiarly-squeezed input name.  (And this is in fact how the lookups are
45# done with the small Perl extension hashes.)  But since we need to be able to
46# go from code point to official name, the original table would still need to
47# exist.  Due to the large size of the table, it was decided to not read
48# another very large string into memory for a second table.  Instead, the
49# regular expression of the input name is modified to have optional spaces and
50# dashes between characters.  For example, in strict matching, the regular
51# expression would be:
52#   qr/\tDIGIT ONE$/m
53# Under loose matching, the blank would be squeezed out, and the re would be:
54#   qr/\tD[- ]?I[- ]?G[- ]?I[- ]?T[- ]?O[- ]?N[- ]?E$/m
55# which matches a blank or dash between any characters in the official table.
56#
57# This is also how script lookup is done.  Basically the re looks like
58#   qr/ (?:LATIN|GREEK|CYRILLIC) (?:SMALL )?LETTER $name/
59# where $name is the loose or strict regex for the remainder of the name.
60
61# The hashes are stored as utf8 strings.  This makes it easier to deal with
62# sequences.  I (khw) also tried making Name.pl utf8, but it slowed things
63# down by a factor of 7.  I then tried making Name.pl store the ut8
64# equivalents but not calling them utf8.  That led to similar speed as leaving
65# it alone, but since that is harder for a human to parse, I left it as-is.
66
67my %system_aliases = (
68
69    'SINGLE-SHIFT 2'                => pack("U", utf8::unicode_to_native(0x8E)),
70    'SINGLE-SHIFT 3'                => pack("U", utf8::unicode_to_native(0x8F)),
71    'PRIVATE USE 1'                 => pack("U", utf8::unicode_to_native(0x91)),
72    'PRIVATE USE 2'                 => pack("U", utf8::unicode_to_native(0x92)),
73);
74
75# These are the aliases above that differ under :loose and :full matching
76# because the :full versions have blanks or hyphens in them.
77#my %loose_system_aliases = (
78#);
79
80#my %deprecated_aliases;
81#$deprecated_aliases{'BELL'} = pack("U", utf8::unicode_to_native(0x07)) if $^V lt v5.17.0;
82
83#my %loose_deprecated_aliases = (
84#);
85
86# These are special cased in :loose matching, differing only in a medial
87# hyphen
88my $HANGUL_JUNGSEONG_O_E_utf8 = pack("U", 0x1180);
89my $HANGUL_JUNGSEONG_OE_utf8 = pack("U", 0x116C);
90
91
92my $txt;  # The table of official character names
93
94my %full_names_cache; # Holds already-looked-up names, so don't have to
95# re-look them up again.  The previous versions of charnames had scoping
96# bugs.  For example if we use script A in one scope and find and cache
97# what Z resolves to, we can't use that cache in a different scope that
98# uses script B instead of A, as Z might be an entirely different letter
99# there; or there might be different aliases in effect in different
100# scopes, or :short may be in effect or not effect in different scopes,
101# or various combinations thereof.  This was solved in this version
102# mostly by moving things to %^H.  But some things couldn't be moved
103# there.  One of them was the cache of runtime looked-up names, in part
104# because %^H is read-only at runtime.  I (khw) don't know why the cache
105# was run-time only in the previous versions: perhaps oversight; perhaps
106# that compile time looking doesn't happen in a loop so didn't think it
107# was worthwhile; perhaps not wanting to make the cache too large.  But
108# I decided to make it compile time as well; this could easily be
109# changed.
110# Anyway, this hash is not scoped, and is added to at runtime.  It
111# doesn't have scoping problems because the data in it is restricted to
112# official names, which are always invariant, and we only set it and
113# look at it at during :full lookups, so is unaffected by any other
114# scoped options.  I put this in to maintain parity with the older
115# version.  If desired, a %short_names cache could also be made, as well
116# as one for each script, say in %script_names_cache, with each key
117# being a hash for a script named in a 'use charnames' statement.  I
118# decided not to do that for now, just because it's added complication,
119# and because I'm just trying to maintain parity, not extend it.
120
121# Like %full_names_cache, but for use when :loose is in effect.  There needs
122# to be two caches because :loose may not be in effect for a scope, and a
123# loose name could inappropriately be returned when only exact matching is
124# called for.
125my %loose_names_cache;
126
127# Designed so that test decimal first, and then hex.  Leading zeros
128# imply non-decimal, as do non-[0-9]
129my $decimal_qr = qr/^[1-9]\d*$/;
130
131# Returns the hex number in $1.
132my $hex_qr = qr/^(?:[Uu]\+|0[xX])?([[:xdigit:]]+)$/;
133
134sub croak
135{
136  require Carp; goto &Carp::croak;
137} # croak
138
139sub carp
140{
141  require Carp; goto &Carp::carp;
142} # carp
143
144sub alias (@) # Set up a single alias
145{
146  my @errors;
147
148  my $alias = ref $_[0] ? $_[0] : { @_ };
149  foreach my $name (sort keys %$alias) {  # Sort only because it helps having
150                                          # deterministic output for
151                                          # t/lib/charnames/alias
152    my $value = $alias->{$name};
153    next unless defined $value;          # Omit if screwed up.
154
155    # Is slightly slower to just after this statement see if it is
156    # decimal, since we already know it is after having converted from
157    # hex, but makes the code easier to maintain, and is called
158    # infrequently, only at compile-time
159    if ($value !~ $decimal_qr && $value =~ $hex_qr) {
160      my $temp = CORE::hex $1;
161      $temp = utf8::unicode_to_native($temp) if $value =~ /^[Uu]\+/;
162      $value = $temp;
163    }
164    if ($value =~ $decimal_qr) {
165        no warnings qw(non_unicode surrogate nonchar); # Allow any of these
166        $^H{charnames_ord_aliases}{$name} = pack("U", $value);
167
168        # Use a canonical form.
169        $^H{charnames_inverse_ords}{sprintf("%05X", $value)} = $name;
170    }
171    else {
172        # This regex needs to be sync'd with the code in toke.c that checks
173        # for the same thing
174        if ($name !~ / ^
175                       \p{_Perl_Charname_Begin}
176                       \p{_Perl_Charname_Continue}*
177                       $ /x) {
178
179          push @errors, $name;
180        }
181        else {
182          $^H{charnames_name_aliases}{$name} = $value;
183
184          if (warnings::enabled('deprecated')) {
185            if ($name =~ / ( .* \s ) ( \s* ) $ /x) {
186              carp "Trailing white-space in a charnames alias definition is deprecated; marked by <-- HERE in '$1 <-- HERE " . $2 . "'";
187            }
188
189            # Use '+' instead of '*' in this regex, because any trailing
190            # blanks have already been warned about.
191            if ($name =~ / ( .*? \s{2} ) ( .+ ) /x) {
192              carp "A sequence of multiple spaces in a charnames alias definition is deprecated; marked by <-- HERE in '$1 <-- HERE " . $2 . "'";
193            }
194          }
195        }
196    }
197  }
198
199  # We find and output all errors from this :alias definition, rather than
200  # failing on the first one, so fewer runs are needed to get it to compile
201  if (@errors) {
202    foreach my $name (@errors) {
203      my $ok = "";
204      my $nbsp = chr utf8::unicode_to_native(0xa0);
205      $ok = $1 if $name =~ / ^ ( \p{Alpha} [-\p{XPosixWord} ():$nbsp]* ) /x;
206      my $first_bad = substr($name, length($ok), 1);
207      $name = "Invalid character in charnames alias definition; marked by <-- HERE in '$ok$first_bad<-- HERE " . substr($name, length($ok) + 1) . "'";
208    }
209    croak join "\n", @errors;
210  }
211
212  return;
213} # alias
214
215sub not_legal_use_bytes_msg {
216  my ($name, $utf8) = @_;
217  my $return;
218
219  if (length($utf8) == 1) {
220    $return = sprintf("Character 0x%04x with name '%s' is", ord $utf8, $name);
221  } else {
222    $return = sprintf("String with name '%s' (and ordinals %s) contains character(s)", $name, join(" ", map { sprintf "0x%04X", ord $_ } split(//, $utf8)));
223  }
224  return $return . " above 0xFF with 'use bytes' in effect";
225}
226
227sub alias_file ($)  # Reads a file containing alias definitions
228{
229  my ($arg, $file) = @_;
230  if (-f $arg && File::Spec->file_name_is_absolute ($arg)) {
231    $file = $arg;
232  }
233  elsif ($arg =~ m/ ^ \p{_Perl_IDStart} \p{_Perl_IDCont}* $/x) {
234    $file = "unicore/${arg}_alias.pl";
235  }
236  else {
237    croak "Charnames alias file names can only have identifier characters";
238  }
239  if (my @alias = do $file) {
240    @alias == 1 && !defined $alias[0] and
241      croak "$file cannot be used as alias file for charnames";
242    @alias % 2 and
243      croak "$file did not return a (valid) list of alias pairs";
244    alias (@alias);
245    return (1);
246  }
247  0;
248} # alias_file
249
250# For use when don't import anything.  This structure must be kept in
251# sync with the one that import() fills up.
252my %dummy_H = (
253                charnames_stringified_names => "",
254                charnames_stringified_ords => "",
255                charnames_scripts => "",
256                charnames_full => 1,
257                charnames_loose => 0,
258                charnames_short => 0,
259              );
260
261
262sub lookup_name ($$$) {
263  my ($name, $wants_ord, $runtime) = @_;
264
265  # Lookup the name or sequence $name in the tables.  If $wants_ord is false,
266  # returns the string equivalent of $name; if true, returns the ordinal value
267  # instead, but in this case $name must not be a sequence; otherwise undef is
268  # returned and a warning raised.  $runtime is 0 if compiletime, otherwise
269  # gives the number of stack frames to go back to get the application caller
270  # info.
271  # If $name is not found, returns undef in runtime with no warning; and in
272  # compiletime, the Unicode replacement character, with a warning.
273
274  # It looks first in the aliases, then in the large table of official Unicode
275  # names.
276
277  my $utf8;       # The string result
278  my $save_input;
279
280  if ($runtime) {
281
282    my $hints_ref = (caller($runtime))[10];
283
284    # If we didn't import anything (which happens with 'use charnames ()',
285    # substitute a dummy structure.
286    $hints_ref = \%dummy_H if ! defined $hints_ref
287                              || (! defined $hints_ref->{charnames_full}
288                                  && ! defined $hints_ref->{charnames_loose});
289
290    # At runtime, but currently not at compile time, $^H gets
291    # stringified, so un-stringify back to the original data structures.
292    # These get thrown away by perl before the next invocation
293    # Also fill in the hash with the non-stringified data.
294    # N.B.  New fields must be also added to %dummy_H
295
296    %{$^H{charnames_name_aliases}} = split ',',
297                                      $hints_ref->{charnames_stringified_names};
298    %{$^H{charnames_ord_aliases}} = split ',',
299                                      $hints_ref->{charnames_stringified_ords};
300    $^H{charnames_scripts} = $hints_ref->{charnames_scripts};
301    $^H{charnames_full} = $hints_ref->{charnames_full};
302    $^H{charnames_loose} = $hints_ref->{charnames_loose};
303    $^H{charnames_short} = $hints_ref->{charnames_short};
304  }
305
306  my $loose = $^H{charnames_loose};
307  my $lookup_name;  # Input name suitably modified for grepping for in the
308                    # table
309
310  # User alias should be checked first or else can't override ours, and if we
311  # were to add any, could conflict with theirs.
312  if (exists $^H{charnames_ord_aliases}{$name}) {
313    $utf8 = $^H{charnames_ord_aliases}{$name};
314  }
315  elsif (exists $^H{charnames_name_aliases}{$name}) {
316    $name = $^H{charnames_name_aliases}{$name};
317    $save_input = $lookup_name = $name;  # Cache the result for any error
318                                         # message
319    # The aliases are documented to not match loosely, so change loose match
320    # into full.
321    if ($loose) {
322      $loose = 0;
323      $^H{charnames_full} = 1;
324    }
325  }
326  else {
327
328    # Here, not a user alias.  That means that loose matching may be in
329    # effect; will have to modify the input name.
330    $lookup_name = $name;
331    if ($loose) {
332      $lookup_name = uc $lookup_name;
333
334      # Squeeze out all underscores
335      $lookup_name =~ s/_//g;
336
337      # Remove all medial hyphens
338      $lookup_name =~ s/ (?<= \S  ) - (?= \S  )//gx;
339
340      # Squeeze out all spaces
341      $lookup_name =~ s/\s//g;
342    }
343
344    # Here, $lookup_name has been modified as necessary for looking in the
345    # hashes.  Check the system alias files next.  Most of these aliases are
346    # the same for both strict and loose matching.  To save space, the ones
347    # which differ are in their own separate hash, which is checked if loose
348    # matching is selected and the regular match fails.  To save time, the
349    # loose hashes could be expanded to include all aliases, and there would
350    # only have to be one check.  But if someone specifies :loose, they are
351    # interested in convenience over speed, and the time for this second check
352    # is miniscule compared to the rest of the routine.
353    if (exists $system_aliases{$lookup_name}) {
354      $utf8 = $system_aliases{$lookup_name};
355    }
356    # There are currently no entries in this hash, so don't waste time looking
357    # for them.  But the code is retained for the unlikely possibility that
358    # some will be added in the future.
359#    elsif ($loose && exists $loose_system_aliases{$lookup_name}) {
360#      $utf8 = $loose_system_aliases{$lookup_name};
361#    }
362#    if (exists $deprecated_aliases{$lookup_name}) {
363#      require warnings;
364#      warnings::warnif('deprecated',
365#                       "Unicode character name \"$name\" is deprecated, use \""
366#                       . viacode(ord $deprecated_aliases{$lookup_name})
367#                       . "\" instead");
368#      $utf8 = $deprecated_aliases{$lookup_name};
369#    }
370    # There are currently no entries in this hash, so don't waste time looking
371    # for them.  But the code is retained for the unlikely possibility that
372    # some will be added in the future.
373#    elsif ($loose && exists $loose_deprecated_aliases{$lookup_name}) {
374#      require warnings;
375#      warnings::warnif('deprecated',
376#                       "Unicode character name \"$name\" is deprecated, use \""
377#                       . viacode(ord $loose_deprecated_aliases{$lookup_name})
378#                       . "\" instead");
379#      $utf8 = $loose_deprecated_aliases{$lookup_name};
380#    }
381  }
382
383  my @off;  # Offsets into table of pattern match begin and end
384
385  # If haven't found it yet...
386  if (! defined $utf8) {
387
388    # See if has looked this input up earlier.
389    if (! $loose && $^H{charnames_full} && exists $full_names_cache{$name}) {
390      $utf8 = $full_names_cache{$name};
391    }
392    elsif ($loose && exists $loose_names_cache{$name}) {
393      $utf8 = $loose_names_cache{$name};
394    }
395    else { # Here, must do a look-up
396
397      # If full or loose matching succeeded, points to where to cache the
398      # result
399      my $cache_ref;
400
401      ## Suck in the code/name list as a big string.
402      ## Lines look like:
403      ##     "00052\tLATIN CAPITAL LETTER R\n"
404      # or
405      #      "0052 0303\tLATIN CAPITAL LETTER R WITH TILDE\n"
406      $txt = do "unicore/Name.pl" unless $txt;
407
408      ## @off will hold the index into the code/name string of the start and
409      ## end of the name as we find it.
410
411      ## If :loose, look for a loose match; if :full, look for the name
412      ## exactly
413      # First, see if the name is one which is algorithmically determinable.
414      # The subroutine is included in Name.pl.  The table contained in
415      # $txt doesn't contain these.  Experiments show that checking
416      # for these before checking for the regular names has no
417      # noticeable impact on performance for the regular names, but
418      # the other way around slows down finding these immensely.
419      # Algorithmically determinables are not placed in the cache because
420      # that uses up memory, and finding these again is fast.
421      if (($loose || $^H{charnames_full})
422          && (defined (my $ord = charnames::name_to_code_point_special($lookup_name, $loose))))
423      {
424        $utf8 = pack("U", $ord);
425      }
426      else {
427
428        # Not algorithmically determinable; look up in the table.  The name
429        # will be turned into a regex, so quote any meta characters.
430        $lookup_name = quotemeta $lookup_name;
431
432        if ($loose) {
433
434          # For loose matches, $lookup_name has already squeezed out the
435          # non-essential characters.  We have to add in code to make the
436          # squeezed version match the non-squeezed equivalent in the table.
437          # The only remaining hyphens are ones that start or end a word in
438          # the original.  They have been quoted in $lookup_name so they look
439          # like "\-".  Change all other characters except the backslash
440          # quotes for any metacharacters, and the final character, so that
441          # e.g., COLON gets transformed into: /C[- ]?O[- ]?L[- ]?O[- ]?N/
442          $lookup_name =~ s/ (?! \\ -)    # Don't do this to the \- sequence
443                             ( [^-\\] )   # Nor the "-" within that sequence,
444                                          # nor the "\" that quotes metachars,
445                                          # but otherwise put the char into $1
446                             (?=.)        # And don't do it for the final char
447                           /$1\[- \]?/gx; # And add an optional blank or
448                                          # '-' after each $1 char
449
450          # Those remaining hyphens were originally at the beginning or end of
451          # a word, so they can match either a blank before or after, but not
452          # both.  (Keep in mind that they have been quoted, so are a '\-'
453          # sequence)
454          $lookup_name =~ s/\\ -/(?:- | -)/xg;
455        }
456
457        # Do the lookup in the full table if asked for, and if succeeds
458        # save the offsets and set where to cache the result.
459        if (($loose || $^H{charnames_full}) && $txt =~ /\t$lookup_name$/m) {
460          @off = ($-[0] + 1, $+[0]);    # The 1 is for the tab
461          $cache_ref = ($loose) ? \%loose_names_cache : \%full_names_cache;
462        }
463        else {
464
465          # Here, didn't look for, or didn't find the name.
466          # If :short is allowed, see if input is like "greek:Sigma".
467          # Keep in mind that $lookup_name has had the metas quoted.
468          my $scripts_trie = "";
469          my $name_has_uppercase;
470          if (($^H{charnames_short})
471              && $lookup_name =~ /^ (?: \\ \s)*   # Quoted space
472                                    (.+?)         # $1 = the script
473                                    (?: \\ \s)*
474                                    \\ :          # Quoted colon
475                                    (?: \\ \s)*
476                                    (.+?)         # $2 = the name
477                                    (?: \\ \s)* $
478                                  /xs)
479          {
480              # Even in non-loose matching, the script traditionally has been
481              # case insensitive
482              $scripts_trie = "\U$1";
483              $lookup_name = $2;
484
485              # Use original name to find its input casing, but ignore the
486              # script part of that to make the determination.
487              $save_input = $name if ! defined $save_input;
488              $name =~ s/.*?://;
489              $name_has_uppercase = $name =~ /[[:upper:]]/;
490          }
491          else { # Otherwise look in allowed scripts
492              $scripts_trie = $^H{charnames_scripts};
493
494              # Use original name to find its input casing
495              $name_has_uppercase = $name =~ /[[:upper:]]/;
496          }
497
498          my $case = $name_has_uppercase ? "CAPITAL" : "SMALL";
499          return if (! $scripts_trie || $txt !~
500             /\t (?: $scripts_trie ) \ (?:$case\ )? LETTER \ \U$lookup_name $/xm);
501
502          # Here have found the input name in the table.
503          @off = ($-[0] + 1, $+[0]);  # The 1 is for the tab
504        }
505
506        # Here, the input name has been found; we haven't set up the output,
507        # but we know where in the string
508        # the name starts.  The string is set up so that for single characters
509        # (and not named sequences), the name is preceded immediately by a
510        # tab and 5 hex digits for its code, with a \n before those.  Named
511        # sequences won't have the 7th preceding character be a \n.
512        # (Actually, for the very first entry in the table this isn't strictly
513        # true: subtracting 7 will yield -1, and the substr below will
514        # therefore yield the very last character in the table, which should
515        # also be a \n, so the statement works anyway.)
516        if (substr($txt, $off[0] - 7, 1) eq "\n") {
517          $utf8 = pack("U", CORE::hex substr($txt, $off[0] - 6, 5));
518
519          # Handle the single loose matching special case, in which two names
520          # differ only by a single medial hyphen.  If the original had a
521          # hyphen (or more) in the right place, then it is that one.
522          $utf8 = $HANGUL_JUNGSEONG_O_E_utf8
523                  if $loose
524                     && $utf8 eq $HANGUL_JUNGSEONG_OE_utf8
525                     && $name =~ m/O \s* - [-\s]* E/ix;
526                     # Note that this wouldn't work if there were a 2nd
527                     # OE in the name
528        }
529        else {
530
531          # Here, is a named sequence.  Need to go looking for the beginning,
532          # which is just after the \n from the previous entry in the table.
533          # The +1 skips past that newline, or, if the rindex() fails, to put
534          # us to an offset of zero.
535          my $charstart = rindex($txt, "\n", $off[0] - 7) + 1;
536          $utf8 = pack("U*", map { CORE::hex }
537              split " ", substr($txt, $charstart, $off[0] - $charstart - 1));
538        }
539      }
540
541      # Cache the input so as to not have to search the large table
542      # again, but only if it came from the one search that we cache.
543      # (Haven't bothered with the pain of sorting out scoping issues for the
544      # scripts searches.)
545      $cache_ref->{$name} = $utf8 if defined $cache_ref;
546    }
547  }
548
549
550  # Here, have the utf8.  If the return is to be an ord, must be any single
551  # character.
552  if ($wants_ord) {
553    return ord($utf8) if length $utf8 == 1;
554  }
555  else {
556
557    # Here, wants string output.  If utf8 is acceptable, just return what
558    # we've got; otherwise attempt to convert it to non-utf8 and return that.
559    my $in_bytes = ($runtime)
560                   ? (caller $runtime)[8] & $bytes::hint_bits
561                   : $^H & $bytes::hint_bits;
562    return $utf8 if (! $in_bytes || utf8::downgrade($utf8, 1)) # The 1 arg
563                                                  # means don't die on failure
564  }
565
566  # Here, there is an error:  either there are too many characters, or the
567  # result string needs to be non-utf8, and at least one character requires
568  # utf8.  Prefer any official name over the input one for the error message.
569  if (@off) {
570    $name = substr($txt, $off[0], $off[1] - $off[0]) if @off;
571  }
572  else {
573    $name = (defined $save_input) ? $save_input : $_[0];
574  }
575
576  if ($wants_ord) {
577    # Only way to get here in this case is if result too long.  Message
578    # assumes that our only caller that requires single char result is
579    # vianame.
580    carp "charnames::vianame() doesn't handle named sequences ($name).  Use charnames::string_vianame() instead";
581    return;
582  }
583
584  # Only other possible failure here is from use bytes.
585  if ($runtime) {
586    carp not_legal_use_bytes_msg($name, $utf8);
587    return;
588  } else {
589    croak not_legal_use_bytes_msg($name, $utf8);
590  }
591
592} # lookup_name
593
594sub charnames {
595
596  # For \N{...}.  Looks up the character name and returns the string
597  # representation of it.
598
599  # The first 0 arg means wants a string returned; the second that we are in
600  # compile time
601  return lookup_name($_[0], 0, 0);
602}
603
604sub import
605{
606  shift; ## ignore class name
607
608  if (not @_) {
609    carp("'use charnames' needs explicit imports list");
610  }
611  $^H{charnames} = \&charnames ;
612  $^H{charnames_ord_aliases} = {};
613  $^H{charnames_name_aliases} = {};
614  $^H{charnames_inverse_ords} = {};
615  # New fields must be added to %dummy_H, and the code in lookup_name()
616  # that copies fields from the runtime structure
617
618  ##
619  ## fill %h keys with our @_ args.
620  ##
621  my ($promote, %h, @args) = (0);
622  while (my $arg = shift) {
623    if ($arg eq ":alias") {
624      @_ or
625        croak ":alias needs an argument in charnames";
626      my $alias = shift;
627      if (ref $alias) {
628        ref $alias eq "HASH" or
629          croak "Only HASH reference supported as argument to :alias";
630        alias ($alias);
631        $promote = 1;
632        next;
633      }
634      if ($alias =~ m{:(\w+)$}) {
635        $1 eq "full" || $1 eq "loose" || $1 eq "short" and
636          croak ":alias cannot use existing pragma :$1 (reversed order?)";
637        alias_file ($1) and $promote = 1;
638        next;
639      }
640      alias_file ($alias) and $promote = 1;
641      next;
642    }
643    if (substr($arg, 0, 1) eq ':'
644      and ! ($arg eq ":full" || $arg eq ":short" || $arg eq ":loose"))
645    {
646      warn "unsupported special '$arg' in charnames";
647      next;
648    }
649    push @args, $arg;
650  }
651
652  @args == 0 && $promote and @args = (":full");
653  @h{@args} = (1) x @args;
654
655  # Don't leave these undefined as are tested for in lookup_names
656  $^H{charnames_full} = delete $h{':full'} || 0;
657  $^H{charnames_loose} = delete $h{':loose'} || 0;
658  $^H{charnames_short} = delete $h{':short'} || 0;
659  my @scripts = map { uc quotemeta } keys %h;
660
661  ##
662  ## If utf8? warnings are enabled, and some scripts were given,
663  ## see if at least we can find one letter from each script.
664  ##
665  if (warnings::enabled('utf8') && @scripts) {
666    $txt = do "unicore/Name.pl" unless $txt;
667
668    for my $script (@scripts) {
669      if (not $txt =~ m/\t$script (?:CAPITAL |SMALL )?LETTER /) {
670        warnings::warn('utf8',  "No such script: '$script'");
671        $script = quotemeta $script;  # Escape it, for use in the re.
672      }
673    }
674  }
675
676  # %^H gets stringified, so serialize it ourselves so can extract the
677  # real data back later.
678  $^H{charnames_stringified_ords} = join ",", %{$^H{charnames_ord_aliases}};
679  $^H{charnames_stringified_names} = join ",", %{$^H{charnames_name_aliases}};
680  $^H{charnames_stringified_inverse_ords} = join ",", %{$^H{charnames_inverse_ords}};
681
682  # Modify the input script names for loose name matching if that is also
683  # specified, similar to the way the base character name is prepared.  They
684  # don't (currently, and hopefully never will) have dashes.  These go into a
685  # regex, and have already been uppercased and quotemeta'd.  Squeeze out all
686  # input underscores, blanks, and dashes.  Then convert so will match a blank
687  # between any characters.
688  if ($^H{charnames_loose}) {
689    for (my $i = 0; $i < @scripts; $i++) {
690      $scripts[$i] =~ s/[_ -]//g;
691      $scripts[$i] =~ s/ ( [^\\] ) (?= . ) /$1\\ ?/gx;
692    }
693  }
694
695  $^H{charnames_scripts} = join "|", @scripts;  # Stringifiy them as a trie
696} # import
697
698# Cache of already looked-up values.  This is set to only contain
699# official values, and user aliases can't override them, so scoping is
700# not an issue.
701my %viacode;
702
703my $no_name_code_points_re = join "|", map { sprintf("%05X",
704                                             utf8::unicode_to_native($_)) }
705                                            0x80, 0x81, 0x84, 0x99;
706$no_name_code_points_re = qr/$no_name_code_points_re/;
707
708sub viacode {
709
710  # Returns the name of the code point argument
711
712  if (@_ != 1) {
713    carp "charnames::viacode() expects one argument";
714    return;
715  }
716
717  my $arg = shift;
718
719  # This is derived from Unicode::UCD, where it is nearly the same as the
720  # function _getcode(), but here it makes sure that even a hex argument
721  # has the proper number of leading zeros, which is critical in
722  # matching against $txt below
723  # Must check if decimal first; see comments at that definition
724  my $hex;
725  if ($arg =~ $decimal_qr) {
726    $hex = sprintf "%05X", $arg;
727  } elsif ($arg =~ $hex_qr) {
728    $hex = CORE::hex $1;
729    $hex = utf8::unicode_to_native($hex) if $arg =~ /^[Uu]\+/;
730    # Below is the line that differs from the _getcode() source
731    $hex = sprintf "%05X", $hex;
732  } else {
733    carp("unexpected arg \"$arg\" to charnames::viacode()");
734    return;
735  }
736
737  return $viacode{$hex} if exists $viacode{$hex};
738
739  my $return;
740
741  # If the code point is above the max in the table, there's no point
742  # looking through it.  Checking the length first is slightly faster
743  if (length($hex) <= 5 || CORE::hex($hex) <= 0x10FFFF) {
744    $txt = do "unicore/Name.pl" unless $txt;
745
746    # See if the name is algorithmically determinable.
747    my $algorithmic = charnames::code_point_to_name_special(CORE::hex $hex);
748    if (defined $algorithmic) {
749      $viacode{$hex} = $algorithmic;
750      return $algorithmic;
751    }
752
753    # Return the official name, if exists.  It's unclear to me (khw) at
754    # this juncture if it is better to return a user-defined override, so
755    # leaving it as is for now.
756    if ($txt =~ m/^$hex\t/m) {
757
758        # The name starts with the next character and goes up to the
759        # next new-line.  Using capturing parentheses above instead of
760        # @+ more than doubles the execution time in Perl 5.13
761        $return = substr($txt, $+[0], index($txt, "\n", $+[0]) - $+[0]);
762
763        # If not one of these 4 code points, return what we've found.
764        if ($hex !~ / ^ $no_name_code_points_re $ /x) {
765          $viacode{$hex} = $return;
766          return $return;
767        }
768
769        # For backwards compatibility, we don't return the official name of
770        # the 4 code points if there are user-defined aliases for them -- so
771        # continue looking.
772    }
773  }
774
775  # See if there is a user name for it, before giving up completely.
776  # First get the scoped aliases, give up if have none.
777  my $H_ref = (caller(1))[10];
778  return if ! defined $return
779              && (! defined $H_ref
780                  || ! exists $H_ref->{charnames_stringified_inverse_ords});
781
782  my %code_point_aliases;
783  if (defined $H_ref->{charnames_stringified_inverse_ords}) {
784    %code_point_aliases = split ',',
785                          $H_ref->{charnames_stringified_inverse_ords};
786    return $code_point_aliases{$hex} if exists $code_point_aliases{$hex};
787  }
788
789  # Here there is no user-defined alias, return any official one.
790  return $return if defined $return;
791
792  if (CORE::hex($hex) > 0x10FFFF
793      && warnings::enabled('non_unicode'))
794  {
795      carp "Unicode characters only allocated up to U+10FFFF (you asked for U+$hex)";
796  }
797  return;
798
799} # viacode
800
8011;
802
803# ex: set ts=8 sts=2 sw=2 et:
804