xref: /openbsd/gnu/usr.bin/perl/lib/_charnames.pm (revision 274d7c50)
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;
9our $VERSION = '1.45';
10use unicore::Name;    # mktables-generated algorithmically-defined names
11
12use bytes ();          # for $bytes::hint_bits
13use re "/aa";          # Everything in here should be ASCII
14
15$Carp::Internal{ (__PACKAGE__) } = 1;
16
17# Translate between Unicode character names and their code points.  This is a
18# submodule of package <charnames>, used to allow \N{...} to be autoloaded,
19# but it was decided not to autoload the various functions in charnames; the
20# splitting allows this behavior.
21#
22# The official names with their code points are stored in a table in
23# lib/unicore/Name.pl which is read in as a large string (almost 3/4 Mb in
24# Unicode 6.0).  Each code point/name combination is separated by a \n in the
25# string.  (Some of the CJK and the Hangul syllable names are instead
26# determined algorithmically via subroutines stored instead in
27# lib/unicore/Name.pm).  Because of the large size of this table, it isn't
28# converted into hashes for faster lookup.
29#
30# But, user defined aliases are stored in their own hashes, as are Perl
31# extensions to the official names.  These are checked first before looking at
32# the official table.
33#
34# Basically, the table is grepped for the input code point (viacode()) or
35# name (the other functions), and the corresponding value on the same line is
36# returned.  The grepping is done by turning the input into a regular
37# expression.  Thus, the same table does double duty, used by both name and
38# code point lookup.  (If we were to have hashes, we would need two, one for
39# each lookup direction.)
40#
41# For loose name matching, the logical thing would be to have a table
42# with all the ignorable characters squeezed out, and then grep it with the
43# similiarly-squeezed input name.  (And this is in fact how the lookups are
44# done with the small Perl extension hashes.)  But since we need to be able to
45# go from code point to official name, the original table would still need to
46# exist.  Due to the large size of the table, it was decided to not read
47# another very large string into memory for a second table.  Instead, the
48# regular expression of the input name is modified to have optional spaces and
49# dashes between characters.  For example, in strict matching, the regular
50# expression would be:
51#   qr/\tDIGIT ONE$/m
52# Under loose matching, the blank would be squeezed out, and the re would be:
53#   qr/\tD[- ]?I[- ]?G[- ]?I[- ]?T[- ]?O[- ]?N[- ]?E$/m
54# which matches a blank or dash between any characters in the official table.
55#
56# This is also how script lookup is done.  Basically the re looks like
57#   qr/ (?:LATIN|GREEK|CYRILLIC) (?:SMALL )?LETTER $name/
58# where $name is the loose or strict regex for the remainder of the name.
59
60# The hashes are stored as utf8 strings.  This makes it easier to deal with
61# sequences.  I (khw) also tried making Name.pl utf8, but it slowed things
62# down by a factor of 7.  I then tried making Name.pl store the ut8
63# equivalents but not calling them utf8.  That led to similar speed as leaving
64# it alone, but since that is harder for a human to parse, I left it as-is.
65
66my %system_aliases = (
67
68    'SINGLE-SHIFT 2'                => chr utf8::unicode_to_native(0x8E),
69    'SINGLE-SHIFT 3'                => chr utf8::unicode_to_native(0x8F),
70    'PRIVATE USE 1'                 => chr utf8::unicode_to_native(0x91),
71    'PRIVATE USE 2'                 => chr utf8::unicode_to_native(0x92),
72);
73
74# These are the aliases above that differ under :loose and :full matching
75# because the :full versions have blanks or hyphens in them.
76#my %loose_system_aliases = (
77#);
78
79#my %deprecated_aliases;
80#$deprecated_aliases{'BELL'} = chr utf8::unicode_to_native(0x07) if $^V lt v5.17.0;
81
82#my %loose_deprecated_aliases = (
83#);
84
85# These are special cased in :loose matching, differing only in a medial
86# hyphen
87my $HANGUL_JUNGSEONG_O_E_utf8 = chr 0x1180;
88my $HANGUL_JUNGSEONG_OE_utf8 = chr 0x116C;
89
90
91my $txt;  # The table of official character names
92
93my %full_names_cache; # Holds already-looked-up names, so don't have to
94# re-look them up again.  The previous versions of charnames had scoping
95# bugs.  For example if we use script A in one scope and find and cache
96# what Z resolves to, we can't use that cache in a different scope that
97# uses script B instead of A, as Z might be an entirely different letter
98# there; or there might be different aliases in effect in different
99# scopes, or :short may be in effect or not effect in different scopes,
100# or various combinations thereof.  This was solved in this version
101# mostly by moving things to %^H.  But some things couldn't be moved
102# there.  One of them was the cache of runtime looked-up names, in part
103# because %^H is read-only at runtime.  I (khw) don't know why the cache
104# was run-time only in the previous versions: perhaps oversight; perhaps
105# that compile time looking doesn't happen in a loop so didn't think it
106# was worthwhile; perhaps not wanting to make the cache too large.  But
107# I decided to make it compile time as well; this could easily be
108# changed.
109# Anyway, this hash is not scoped, and is added to at runtime.  It
110# doesn't have scoping problems because the data in it is restricted to
111# official names, which are always invariant, and we only set it and
112# look at it at during :full lookups, so is unaffected by any other
113# scoped options.  I put this in to maintain parity with the older
114# version.  If desired, a %short_names cache could also be made, as well
115# as one for each script, say in %script_names_cache, with each key
116# being a hash for a script named in a 'use charnames' statement.  I
117# decided not to do that for now, just because it's added complication,
118# and because I'm just trying to maintain parity, not extend it.
119
120# Like %full_names_cache, but for use when :loose is in effect.  There needs
121# to be two caches because :loose may not be in effect for a scope, and a
122# loose name could inappropriately be returned when only exact matching is
123# called for.
124my %loose_names_cache;
125
126# Designed so that test decimal first, and then hex.  Leading zeros
127# imply non-decimal, as do non-[0-9]
128my $decimal_qr = qr/^[1-9]\d*$/;
129
130# Returns the hex number in $1.
131my $hex_qr = qr/^(?:[Uu]\+|0[xX])?([[:xdigit:]]+)$/;
132
133sub croak
134{
135  require Carp; goto &Carp::croak;
136} # croak
137
138sub carp
139{
140  require Carp; goto &Carp::carp;
141} # carp
142
143sub alias (@) # Set up a single alias
144{
145  my @errors;
146  my $nbsp = chr utf8::unicode_to_native(0xA0);
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} = chr $value;
167
168        # Use a canonical form.
169        $^H{charnames_inverse_ords}{sprintf("%05X", $value)} = $name;
170    }
171    else {
172        my $ok_portion = "";
173        $ok_portion = $1 if $name =~ / ^ (
174                                            \p{_Perl_Charname_Begin}
175                                            \p{_Perl_Charname_Continue}*
176                                         ) /x;
177
178        # If the name was fully correct, the above should have matched all of
179        # it.
180        if (length $ok_portion < length $name) {
181          my $first_bad = substr($name, length($ok_portion), 1);
182          push @errors, "Invalid character in charnames alias definition; "
183                        . "marked by <-- HERE in '$ok_portion$first_bad<-- HERE "
184                        . substr($name, length($ok_portion) + 1)
185                        . "'";
186        }
187        else {
188            if ($name =~ / ( .* \s ) ( \s* ) $ /x) {
189              push @errors, "charnames alias definitions may not contain "
190                            . "trailing white-space; marked by <-- HERE in "
191                            . "'$1 <-- HERE " . $2 . "'";
192              next;
193            }
194
195            # Use '+' instead of '*' in this regex, because any trailing
196            # blanks have already been found
197            if ($name =~ / ( .*? \s{2} ) ( .+ ) /x) {
198              push @errors, "charnames alias definitions may not contain a "
199                            . "sequence of multiple spaces; marked by <-- HERE "
200                            . "in '$1 <-- HERE " . $2 . "'";
201              next;
202            }
203
204            $^H{charnames_name_aliases}{$name} = $value;
205        }
206    }
207  }
208
209  # We find and output all errors from this :alias definition, rather than
210  # failing on the first one, so fewer runs are needed to get it to compile
211  if (@errors) {
212    croak join "\n", @errors;
213  }
214
215  return;
216} # alias
217
218sub not_legal_use_bytes_msg {
219  my ($name, $utf8) = @_;
220  my $return;
221
222  if (length($utf8) == 1) {
223    $return = sprintf("Character 0x%04x with name '%s' is", ord $utf8, $name);
224  } else {
225    $return = sprintf("String with name '%s' (and ordinals %s) contains character(s)", $name, join(" ", map { sprintf "0x%04X", ord $_ } split(//, $utf8)));
226  }
227  return $return . " above 0xFF with 'use bytes' in effect";
228}
229
230sub alias_file ($)  # Reads a file containing alias definitions
231{
232  require File::Spec;
233  my ($arg, $file) = @_;
234  if (-f $arg && File::Spec->file_name_is_absolute ($arg)) {
235    $file = $arg;
236  }
237  elsif ($arg =~ m/ ^ \p{_Perl_IDStart} \p{_Perl_IDCont}* $/x) {
238    $file = "unicore/${arg}_alias.pl";
239  }
240  else {
241    croak "Charnames alias file names can only have identifier characters";
242  }
243  if (my @alias = do $file) {
244    @alias == 1 && !defined $alias[0] and
245      croak "$file cannot be used as alias file for charnames";
246    @alias % 2 and
247      croak "$file did not return a (valid) list of alias pairs";
248    alias (@alias);
249    return (1);
250  }
251  0;
252} # alias_file
253
254# For use when don't import anything.  This structure must be kept in
255# sync with the one that import() fills up.
256my %dummy_H = (
257                charnames_stringified_names => "",
258                charnames_stringified_ords => "",
259                charnames_scripts => "",
260                charnames_full => 1,
261                charnames_loose => 0,
262                charnames_short => 0,
263              );
264
265
266sub lookup_name ($$$) {
267  my ($name, $wants_ord, $runtime) = @_;
268
269  # Lookup the name or sequence $name in the tables.  If $wants_ord is false,
270  # returns the string equivalent of $name; if true, returns the ordinal value
271  # instead, but in this case $name must not be a sequence; otherwise undef is
272  # returned and a warning raised.  $runtime is 0 if compiletime, otherwise
273  # gives the number of stack frames to go back to get the application caller
274  # info.
275  # If $name is not found, returns undef in runtime with no warning; and in
276  # compiletime, the Unicode replacement character, with a warning.
277
278  # It looks first in the aliases, then in the large table of official Unicode
279  # names.
280
281  my $result;       # The string result
282  my $save_input;
283
284  if ($runtime) {
285
286    my $hints_ref = (caller($runtime))[10];
287
288    # If we didn't import anything (which happens with 'use charnames ()',
289    # substitute a dummy structure.
290    $hints_ref = \%dummy_H if ! defined $hints_ref
291                              || (! defined $hints_ref->{charnames_full}
292                                  && ! defined $hints_ref->{charnames_loose});
293
294    # At runtime, but currently not at compile time, %^H gets
295    # stringified, so un-stringify back to the original data structures.
296    # These get thrown away by perl before the next invocation
297    # Also fill in the hash with the non-stringified data.
298    # N.B.  New fields must be also added to %dummy_H
299
300    %{$^H{charnames_name_aliases}} = split ',',
301                                      $hints_ref->{charnames_stringified_names};
302    %{$^H{charnames_ord_aliases}} = split ',',
303                                      $hints_ref->{charnames_stringified_ords};
304    $^H{charnames_scripts} = $hints_ref->{charnames_scripts};
305    $^H{charnames_full} = $hints_ref->{charnames_full};
306    $^H{charnames_loose} = $hints_ref->{charnames_loose};
307    $^H{charnames_short} = $hints_ref->{charnames_short};
308  }
309
310  my $loose = $^H{charnames_loose};
311  my $lookup_name;  # Input name suitably modified for grepping for in the
312                    # table
313
314  # User alias should be checked first or else can't override ours, and if we
315  # were to add any, could conflict with theirs.
316  if (exists $^H{charnames_ord_aliases}{$name}) {
317    $result = $^H{charnames_ord_aliases}{$name};
318  }
319  elsif (exists $^H{charnames_name_aliases}{$name}) {
320    $name = $^H{charnames_name_aliases}{$name};
321    $save_input = $lookup_name = $name;  # Cache the result for any error
322                                         # message
323    # The aliases are documented to not match loosely, so change loose match
324    # into full.
325    if ($loose) {
326      $loose = 0;
327      $^H{charnames_full} = 1;
328    }
329  }
330  else {
331
332    # Here, not a user alias.  That means that loose matching may be in
333    # effect; will have to modify the input name.
334    $lookup_name = $name;
335    if ($loose) {
336      $lookup_name = uc $lookup_name;
337
338      # Squeeze out all underscores
339      $lookup_name =~ s/_//g;
340
341      # Remove all medial hyphens
342      $lookup_name =~ s/ (?<= \S  ) - (?= \S  )//gx;
343
344      # Squeeze out all spaces
345      $lookup_name =~ s/\s//g;
346    }
347
348    # Here, $lookup_name has been modified as necessary for looking in the
349    # hashes.  Check the system alias files next.  Most of these aliases are
350    # the same for both strict and loose matching.  To save space, the ones
351    # which differ are in their own separate hash, which is checked if loose
352    # matching is selected and the regular match fails.  To save time, the
353    # loose hashes could be expanded to include all aliases, and there would
354    # only have to be one check.  But if someone specifies :loose, they are
355    # interested in convenience over speed, and the time for this second check
356    # is miniscule compared to the rest of the routine.
357    if (exists $system_aliases{$lookup_name}) {
358      $result = $system_aliases{$lookup_name};
359    }
360    # There are currently no entries in this hash, so don't waste time looking
361    # for them.  But the code is retained for the unlikely possibility that
362    # some will be added in the future.
363#    elsif ($loose && exists $loose_system_aliases{$lookup_name}) {
364#      $result = $loose_system_aliases{$lookup_name};
365#    }
366#    if (exists $deprecated_aliases{$lookup_name}) {
367#      require warnings;
368#      warnings::warnif('deprecated',
369#                       "Unicode character name \"$name\" is deprecated, use \""
370#                       . viacode(ord $deprecated_aliases{$lookup_name})
371#                       . "\" instead");
372#      $result = $deprecated_aliases{$lookup_name};
373#    }
374    # There are currently no entries in this hash, so don't waste time looking
375    # for them.  But the code is retained for the unlikely possibility that
376    # some will be added in the future.
377#    elsif ($loose && exists $loose_deprecated_aliases{$lookup_name}) {
378#      require warnings;
379#      warnings::warnif('deprecated',
380#                       "Unicode character name \"$name\" is deprecated, use \""
381#                       . viacode(ord $loose_deprecated_aliases{$lookup_name})
382#                       . "\" instead");
383#      $result = $loose_deprecated_aliases{$lookup_name};
384#    }
385  }
386
387  my @off;  # Offsets into table of pattern match begin and end
388
389  # If haven't found it yet...
390  if (! defined $result) {
391
392    # See if has looked this input up earlier.
393    if (! $loose && $^H{charnames_full} && exists $full_names_cache{$name}) {
394      $result = $full_names_cache{$name};
395    }
396    elsif ($loose && exists $loose_names_cache{$name}) {
397      $result = $loose_names_cache{$name};
398    }
399    else { # Here, must do a look-up
400
401      # If full or loose matching succeeded, points to where to cache the
402      # result
403      my $cache_ref;
404
405      ## Suck in the code/name list as a big string.
406      ## Lines look like:
407      ##     "00052\tLATIN CAPITAL LETTER R\n"
408      # or
409      #      "0052 0303\tLATIN CAPITAL LETTER R WITH TILDE\n"
410      $txt = do "unicore/Name.pl" unless $txt;
411
412      ## @off will hold the index into the code/name string of the start and
413      ## end of the name as we find it.
414
415      ## If :loose, look for a loose match; if :full, look for the name
416      ## exactly
417      # First, see if the name is one which is algorithmically determinable.
418      # The subroutine is included in Name.pl.  The table contained in
419      # $txt doesn't contain these.  Experiments show that checking
420      # for these before checking for the regular names has no
421      # noticeable impact on performance for the regular names, but
422      # the other way around slows down finding these immensely.
423      # Algorithmically determinables are not placed in the cache because
424      # that uses up memory, and finding these again is fast.
425      if (($loose || $^H{charnames_full})
426          && (defined (my $ord = charnames::name_to_code_point_special($lookup_name, $loose))))
427      {
428        $result = chr $ord;
429      }
430      else {
431
432        # Not algorithmically determinable; look up in the table.  The name
433        # will be turned into a regex, so quote any meta characters.
434        $lookup_name = quotemeta $lookup_name;
435
436        if ($loose) {
437
438          # For loose matches, $lookup_name has already squeezed out the
439          # non-essential characters.  We have to add in code to make the
440          # squeezed version match the non-squeezed equivalent in the table.
441          # The only remaining hyphens are ones that start or end a word in
442          # the original.  They have been quoted in $lookup_name so they look
443          # like "\-".  Change all other characters except the backslash
444          # quotes for any metacharacters, and the final character, so that
445          # e.g., COLON gets transformed into: /C[- ]?O[- ]?L[- ]?O[- ]?N/
446          $lookup_name =~ s/ (?! \\ -)    # Don't do this to the \- sequence
447                             ( [^-\\] )   # Nor the "-" within that sequence,
448                                          # nor the "\" that quotes metachars,
449                                          # but otherwise put the char into $1
450                             (?=.)        # And don't do it for the final char
451                           /$1\[- \]?/gx; # And add an optional blank or
452                                          # '-' after each $1 char
453
454          # Those remaining hyphens were originally at the beginning or end of
455          # a word, so they can match either a blank before or after, but not
456          # both.  (Keep in mind that they have been quoted, so are a '\-'
457          # sequence)
458          $lookup_name =~ s/\\ -/(?:- | -)/xg;
459        }
460
461        # Do the lookup in the full table if asked for, and if succeeds
462        # save the offsets and set where to cache the result.
463        if (($loose || $^H{charnames_full}) && $txt =~ /\t$lookup_name$/m) {
464          @off = ($-[0] + 1, $+[0]);    # The 1 is for the tab
465          $cache_ref = ($loose) ? \%loose_names_cache : \%full_names_cache;
466        }
467        else {
468
469          # Here, didn't look for, or didn't find the name.
470          # If :short is allowed, see if input is like "greek:Sigma".
471          # Keep in mind that $lookup_name has had the metas quoted.
472          my $scripts_trie = "";
473          my $name_has_uppercase;
474          if (($^H{charnames_short})
475              && $lookup_name =~ /^ (?: \\ \s)*   # Quoted space
476                                    (.+?)         # $1 = the script
477                                    (?: \\ \s)*
478                                    \\ :          # Quoted colon
479                                    (?: \\ \s)*
480                                    (.+?)         # $2 = the name
481                                    (?: \\ \s)* $
482                                  /xs)
483          {
484              # Even in non-loose matching, the script traditionally has been
485              # case insensitive
486              $scripts_trie = "\U$1";
487              $lookup_name = $2;
488
489              # Use original name to find its input casing, but ignore the
490              # script part of that to make the determination.
491              $save_input = $name if ! defined $save_input;
492              $name =~ s/.*?://;
493              $name_has_uppercase = $name =~ /[[:upper:]]/;
494          }
495          else { # Otherwise look in allowed scripts
496              $scripts_trie = $^H{charnames_scripts};
497
498              # Use original name to find its input casing
499              $name_has_uppercase = $name =~ /[[:upper:]]/;
500          }
501
502          my $case = $name_has_uppercase ? "CAPITAL" : "SMALL";
503          return if (! $scripts_trie || $txt !~
504             /\t (?: $scripts_trie ) \ (?:$case\ )? LETTER \ \U$lookup_name $/xm);
505
506          # Here have found the input name in the table.
507          @off = ($-[0] + 1, $+[0]);  # The 1 is for the tab
508        }
509
510        # Here, the input name has been found; we haven't set up the output,
511        # but we know where in the string
512        # the name starts.  The string is set up so that for single characters
513        # (and not named sequences), the name is preceded immediately by a
514        # tab and 5 hex digits for its code, with a \n before those.  Named
515        # sequences won't have the 7th preceding character be a \n.
516        # (Actually, for the very first entry in the table this isn't strictly
517        # true: subtracting 7 will yield -1, and the substr below will
518        # therefore yield the very last character in the table, which should
519        # also be a \n, so the statement works anyway.)
520        if (substr($txt, $off[0] - 7, 1) eq "\n") {
521          $result = chr CORE::hex substr($txt, $off[0] - 6, 5);
522
523          # Handle the single loose matching special case, in which two names
524          # differ only by a single medial hyphen.  If the original had a
525          # hyphen (or more) in the right place, then it is that one.
526          $result = $HANGUL_JUNGSEONG_O_E_utf8
527                  if $loose
528                     && $result eq $HANGUL_JUNGSEONG_OE_utf8
529                     && $name =~ m/O \s* - [-\s]* E/ix;
530                     # Note that this wouldn't work if there were a 2nd
531                     # OE in the name
532        }
533        else {
534
535          # Here, is a named sequence.  Need to go looking for the beginning,
536          # which is just after the \n from the previous entry in the table.
537          # The +1 skips past that newline, or, if the rindex() fails, to put
538          # us to an offset of zero.
539          my $charstart = rindex($txt, "\n", $off[0] - 7) + 1;
540          $result = pack("W*", map { CORE::hex }
541              split " ", substr($txt, $charstart, $off[0] - $charstart - 1));
542        }
543      }
544
545      # Cache the input so as to not have to search the large table
546      # again, but only if it came from the one search that we cache.
547      # (Haven't bothered with the pain of sorting out scoping issues for the
548      # scripts searches.)
549      $cache_ref->{$name} = $result if defined $cache_ref;
550    }
551  }
552
553  # Here, have the result character.  If the return is to be an ord, must be
554  # any single character.
555  if ($wants_ord) {
556    return ord($result) if length $result == 1;
557  }
558  elsif (! utf8::is_utf8($result)) {
559
560    # Here isn't UTF-8.  That's OK if it is all ASCII, or we are being called
561    # at compile time where we know we can guarantee that Unicode rules are
562    # correctly imposed on the result, or under 'bytes' where we don't want
563    # those rules.  But otherwise we have to make it UTF8 to guarantee Unicode
564    # rules on the returned string.
565    return $result if ! $runtime
566                      || (caller $runtime)[8] & $bytes::hint_bits
567                      || $result !~ /[[:^ascii:]]/;
568    utf8::upgrade($result);
569    return $result;
570  }
571  else {
572
573    # Here, wants string output.  If utf8 is acceptable, just return what
574    # we've got; otherwise attempt to convert it to non-utf8 and return that.
575    my $in_bytes = ($runtime)
576                   ? (caller $runtime)[8] & $bytes::hint_bits
577                   : $^H & $bytes::hint_bits;
578    return $result if (! $in_bytes || utf8::downgrade($result, 1)) # The 1 arg
579                                                  # means don't die on failure
580  }
581
582  # Here, there is an error:  either there are too many characters, or the
583  # result string needs to be non-utf8, and at least one character requires
584  # utf8.  Prefer any official name over the input one for the error message.
585  if (@off) {
586    $name = substr($txt, $off[0], $off[1] - $off[0]) if @off;
587  }
588  else {
589    $name = (defined $save_input) ? $save_input : $_[0];
590  }
591
592  if ($wants_ord) {
593    # Only way to get here in this case is if result too long.  Message
594    # assumes that our only caller that requires single char result is
595    # vianame.
596    carp "charnames::vianame() doesn't handle named sequences ($name).  Use charnames::string_vianame() instead";
597    return;
598  }
599
600  # Only other possible failure here is from use bytes.
601  if ($runtime) {
602    carp not_legal_use_bytes_msg($name, $result);
603    return;
604  } else {
605    croak not_legal_use_bytes_msg($name, $result);
606  }
607
608} # lookup_name
609
610sub charnames {
611
612  # For \N{...}.  Looks up the character name and returns the string
613  # representation of it.
614
615  # The first 0 arg means wants a string returned; the second that we are in
616  # compile time
617  return lookup_name($_[0], 0, 0);
618}
619
620sub import
621{
622  shift; ## ignore class name
623
624  if (not @_) {
625    carp("'use charnames' needs explicit imports list");
626  }
627  $^H{charnames} = \&charnames ;
628  $^H{charnames_ord_aliases} = {};
629  $^H{charnames_name_aliases} = {};
630  $^H{charnames_inverse_ords} = {};
631  # New fields must be added to %dummy_H, and the code in lookup_name()
632  # that copies fields from the runtime structure
633
634  ##
635  ## fill %h keys with our @_ args.
636  ##
637  my ($promote, %h, @args) = (0);
638  while (my $arg = shift) {
639    if ($arg eq ":alias") {
640      @_ or
641        croak ":alias needs an argument in charnames";
642      my $alias = shift;
643      if (ref $alias) {
644        ref $alias eq "HASH" or
645          croak "Only HASH reference supported as argument to :alias";
646        alias ($alias);
647        $promote = 1;
648        next;
649      }
650      if ($alias =~ m{:(\w+)$}) {
651        $1 eq "full" || $1 eq "loose" || $1 eq "short" and
652          croak ":alias cannot use existing pragma :$1 (reversed order?)";
653        alias_file ($1) and $promote = 1;
654        next;
655      }
656      alias_file ($alias) and $promote = 1;
657      next;
658    }
659    if (substr($arg, 0, 1) eq ':'
660      and ! ($arg eq ":full" || $arg eq ":short" || $arg eq ":loose"))
661    {
662      warn "unsupported special '$arg' in charnames";
663      next;
664    }
665    push @args, $arg;
666  }
667
668  @args == 0 && $promote and @args = (":full");
669  @h{@args} = (1) x @args;
670
671  # Don't leave these undefined as are tested for in lookup_names
672  $^H{charnames_full} = delete $h{':full'} || 0;
673  $^H{charnames_loose} = delete $h{':loose'} || 0;
674  $^H{charnames_short} = delete $h{':short'} || 0;
675  my @scripts = map { uc quotemeta } keys %h;
676
677  ##
678  ## If utf8? warnings are enabled, and some scripts were given,
679  ## see if at least we can find one letter from each script.
680  ##
681  if (warnings::enabled('utf8') && @scripts) {
682    $txt = do "unicore/Name.pl" unless $txt;
683
684    for my $script (@scripts) {
685      if (not $txt =~ m/\t$script (?:CAPITAL |SMALL )?LETTER /) {
686        warnings::warn('utf8',  "No such script: '$script'");
687        $script = quotemeta $script;  # Escape it, for use in the re.
688      }
689    }
690  }
691
692  # %^H gets stringified, so serialize it ourselves so can extract the
693  # real data back later.
694  $^H{charnames_stringified_ords} = join ",", %{$^H{charnames_ord_aliases}};
695  $^H{charnames_stringified_names} = join ",", %{$^H{charnames_name_aliases}};
696  $^H{charnames_stringified_inverse_ords} = join ",", %{$^H{charnames_inverse_ords}};
697
698  # Modify the input script names for loose name matching if that is also
699  # specified, similar to the way the base character name is prepared.  They
700  # don't (currently, and hopefully never will) have dashes.  These go into a
701  # regex, and have already been uppercased and quotemeta'd.  Squeeze out all
702  # input underscores, blanks, and dashes.  Then convert so will match a blank
703  # between any characters.
704  if ($^H{charnames_loose}) {
705    for (my $i = 0; $i < @scripts; $i++) {
706      $scripts[$i] =~ s/[_ -]//g;
707      $scripts[$i] =~ s/ ( [^\\] ) (?= . ) /$1\\ ?/gx;
708    }
709  }
710
711  $^H{charnames_scripts} = join "|", @scripts;  # Stringifiy them as a trie
712} # import
713
714# Cache of already looked-up values.  This is set to only contain
715# official values, and user aliases can't override them, so scoping is
716# not an issue.
717my %viacode;
718
719my $no_name_code_points_re = join "|", map { sprintf("%05X",
720                                             utf8::unicode_to_native($_)) }
721                                            0x80, 0x81, 0x84, 0x99;
722$no_name_code_points_re = qr/$no_name_code_points_re/;
723
724sub viacode {
725
726  # Returns the name of the code point argument
727
728  if (@_ != 1) {
729    carp "charnames::viacode() expects one argument";
730    return;
731  }
732
733  my $arg = shift;
734
735  # This is derived from Unicode::UCD, where it is nearly the same as the
736  # function _getcode(), but here it makes sure that even a hex argument
737  # has the proper number of leading zeros, which is critical in
738  # matching against $txt below
739  # Must check if decimal first; see comments at that definition
740  my $hex;
741  if ($arg =~ $decimal_qr) {
742    $hex = sprintf "%05X", $arg;
743  } elsif ($arg =~ $hex_qr) {
744    $hex = CORE::hex $1;
745    $hex = utf8::unicode_to_native($hex) if $arg =~ /^[Uu]\+/;
746    # Below is the line that differs from the _getcode() source
747    $hex = sprintf "%05X", $hex;
748  } else {
749    carp("unexpected arg \"$arg\" to charnames::viacode()");
750    return;
751  }
752
753  return $viacode{$hex} if exists $viacode{$hex};
754
755  my $return;
756
757  # If the code point is above the max in the table, there's no point
758  # looking through it.  Checking the length first is slightly faster
759  if (length($hex) <= 5 || CORE::hex($hex) <= 0x10FFFF) {
760    $txt = do "unicore/Name.pl" unless $txt;
761
762    # See if the name is algorithmically determinable.
763    my $algorithmic = charnames::code_point_to_name_special(CORE::hex $hex);
764    if (defined $algorithmic) {
765      $viacode{$hex} = $algorithmic;
766      return $algorithmic;
767    }
768
769    # Return the official name, if exists.  It's unclear to me (khw) at
770    # this juncture if it is better to return a user-defined override, so
771    # leaving it as is for now.
772    if ($txt =~ m/^$hex\t/m) {
773
774        # The name starts with the next character and goes up to the
775        # next new-line.  Using capturing parentheses above instead of
776        # @+ more than doubles the execution time in Perl 5.13
777        $return = substr($txt, $+[0], index($txt, "\n", $+[0]) - $+[0]);
778
779        # If not one of these 4 code points, return what we've found.
780        if ($hex !~ / ^ $no_name_code_points_re $ /x) {
781          $viacode{$hex} = $return;
782          return $return;
783        }
784
785        # For backwards compatibility, we don't return the official name of
786        # the 4 code points if there are user-defined aliases for them -- so
787        # continue looking.
788    }
789  }
790
791  # See if there is a user name for it, before giving up completely.
792  # First get the scoped aliases, give up if have none.
793  my $H_ref = (caller(1))[10];
794  return if ! defined $return
795              && (! defined $H_ref
796                  || ! exists $H_ref->{charnames_stringified_inverse_ords});
797
798  my %code_point_aliases;
799  if (defined $H_ref->{charnames_stringified_inverse_ords}) {
800    %code_point_aliases = split ',',
801                          $H_ref->{charnames_stringified_inverse_ords};
802    return $code_point_aliases{$hex} if exists $code_point_aliases{$hex};
803  }
804
805  # Here there is no user-defined alias, return any official one.
806  return $return if defined $return;
807
808  if (CORE::hex($hex) > 0x10FFFF
809      && warnings::enabled('non_unicode'))
810  {
811      carp "Unicode characters only allocated up to U+10FFFF (you asked for U+$hex)";
812  }
813  return;
814
815} # viacode
816
8171;
818
819# ex: set ts=8 sts=2 sw=2 et:
820