perl/lib/charnames.pm

package charnames;
use strict;
use warnings;
use Carp;
use File::Spec;
our $VERSION = '1.04';

use bytes ();           # for $bytes::hint_bits
$charnames::hint_bits = 0x20000; # HINT_LOCALIZE_HH

my %alias1 = (
                # Icky 3.2 names with parentheses.
                'LINE FEED'             => 'LINE FEED (LF)',
                'FORM FEED'             => 'FORM FEED (FF)',
                'CARRIAGE RETURN'       => 'CARRIAGE RETURN (CR)',
                'NEXT LINE'             => 'NEXT LINE (NEL)',
                # Convenience.
                'LF'                    => 'LINE FEED (LF)',
                'FF'                    => 'FORM FEED (FF)',
                'CR'                    => 'CARRIAGE RETURN (CR)',
                'NEL'                   => 'NEXT LINE (NEL)',
                # More convenience.  For futher convencience,
                # it is suggested some way using using the NamesList
                # aliases is implemented.
                'ZWNJ'                  => 'ZERO WIDTH NON-JOINER',
                'ZWJ'                   => 'ZERO WIDTH JOINER',
                'BOM'                   => 'BYTE ORDER MARK',
            );

my %alias2 = (
                # Pre-3.2 compatibility (only for the first 256 characters).
                'HORIZONTAL TABULATION' => 'CHARACTER TABULATION',
                'VERTICAL TABULATION'   => 'LINE TABULATION',
                'FILE SEPARATOR'        => 'INFORMATION SEPARATOR FOUR',
                'GROUP SEPARATOR'       => 'INFORMATION SEPARATOR THREE',
                'RECORD SEPARATOR'      => 'INFORMATION SEPARATOR TWO',
                'UNIT SEPARATOR'        => 'INFORMATION SEPARATOR ONE',
                'PARTIAL LINE DOWN'     => 'PARTIAL LINE FORWARD',
                'PARTIAL LINE UP'       => 'PARTIAL LINE BACKWARD',
            );

my %alias3 = (
                # User defined aliasses. Even more convenient :)
            );
my $txt;

sub alias (@)
{
  @_ or return %alias3;
  my $alias = ref $_[0] ? $_[0] : { @_ };
  @alias3{keys %$alias} = values %$alias;
} # alias

sub alias_file ($)
{
  my ($arg, $file) = @_;
  if (-f $arg && File::Spec->file_name_is_absolute ($arg)) {
    $file = $arg;
  }
  elsif ($arg =~ m/^\w+$/) {
    $file = "unicore/${arg}_alias.pl";
  }
  else {
    croak "Charnames alias files can only have identifier characters";
  }
  if (my @alias = do $file) {
    @alias == 1 && !defined $alias[0] and
      croak "$file cannot be used as alias file for charnames";
    @alias % 2 and
      croak "$file did not return a (valid) list of alias pairs";
    alias (@alias);
    return (1);
  }
  0;
} # alias_file

# This is not optimized in any way yet
sub charnames
{
  my $name = shift;

  if (exists $alias1{$name}) {
    $name = $alias1{$name};
  }
  elsif (exists $alias2{$name}) {
    require warnings;
    warnings::warnif('deprecated', qq{Unicode character name "$name" is deprecated, use "$alias2{$name}" instead});
    $name = $alias2{$name};
  }
  elsif (exists $alias3{$name}) {
    $name = $alias3{$name};
  }

  my $ord;
  my @off;
  my $fname;

  if ($name eq "BYTE ORDER MARK") {
    $fname = $name;
    $ord = 0xFEFF;
  } else {
    ## Suck in the code/name list as a big string.
    ## Lines look like:
    ##     "0052\t\tLATIN CAPITAL LETTER R\n"
    $txt = do "unicore/Name.pl" unless $txt;

    ## @off will hold the index into the code/name string of the start and
    ## end of the name as we find it.

    ## If :full, look for the name exactly
    if ($^H{charnames_full} and $txt =~ /\t\t\Q$name\E$/m) {
      @off = ($-[0], $+[0]);
    }

    ## If we didn't get above, and :short allowed, look for the short name.
    ## The short name is like "greek:Sigma"
    unless (@off) {
      if ($^H{charnames_short} and $name =~ /^(.+?):(.+)/s) {
        my ($script, $cname) = ($1, $2);
        my $case = $cname =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL";
        if ($txt =~ m/\t\t\U$script\E (?:$case )?LETTER \U\Q$cname\E$/m) {
          @off = ($-[0], $+[0]);
        }
      }
    }

    ## If we still don't have it, check for the name among the loaded
    ## scripts.
    if (not @off) {
      my $case = $name =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL";
      for my $script (@{$^H{charnames_scripts}}) {
        if ($txt =~ m/\t\t$script (?:$case )?LETTER \U\Q$name\E$/m) {
          @off = ($-[0], $+[0]);
          last;
        }
      }
    }

    ## If we don't have it by now, give up.
    unless (@off) {
      carp "Unknown charname '$name'";
      return "\x{FFFD}";
    }

    ##
    ## Now know where in the string the name starts.
    ## The code, in hex, is before that.
    ##
    ## The code can be 4-6 characters long, so we've got to sort of
    ## go look for it, just after the newline that comes before $off[0].
    ##
    ## This would be much easier if unicore/Name.pl had info in
    ## a name/code order, instead of code/name order.
    ##
    ## The +1 after the rindex() is to skip past the newline we're finding,
    ## or, if the rindex() fails, to put us to an offset of zero.
    ##
    my $hexstart = rindex($txt, "\n", $off[0]) + 1;

    ## we know where it starts, so turn into number -
    ## the ordinal for the char.
    $ord = hex substr($txt, $hexstart, $off[0] - $hexstart);
  }

  if ($^H & $bytes::hint_bits) {        # "use bytes" in effect?
    use bytes;
    return chr $ord if $ord <= 255;
    my $hex = sprintf "%04x", $ord;
    if (not defined $fname) {
      $fname = substr $txt, $off[0] + 2, $off[1] - $off[0] - 2;
    }
    croak "Character 0x$hex with name '$fname' is above 0xFF";
  }

  no warnings 'utf8'; # allow even illegal characters
  return pack "U", $ord;
} # charnames

sub import
{
  shift; ## ignore class name

  if (not @_) {
    carp("`use charnames' needs explicit imports list");
  }
  $^H |= $charnames::hint_bits;
  $^H{charnames} = \&charnames ;

  ##
  ## fill %h keys with our @_ args.
  ##
  my ($promote, %h, @args) = (0);
  while (my $arg = shift) {
    if ($arg eq ":alias") {
      @_ or
        croak ":alias needs an argument in charnames";
      my $alias = shift;
      if (ref $alias) {
        ref $alias eq "HASH" or
          croak "Only HASH reference supported as argument to :alias";
        alias ($alias);
        next;
      }
      if ($alias =~ m{:(\w+)$}) {
        $1 eq "full" || $1 eq "short" and
          croak ":alias cannot use existing pragma :$1 (reversed order?)";
        alias_file ($1) and $promote = 1;
        next;
      }
      alias_file ($alias);
      next;
    }
    if (substr($arg, 0, 1) eq ':' and ! ($arg eq ":full" || $arg eq ":short")) {
      warn "unsupported special '$arg' in charnames";
      next;
    }
    push @args, $arg;
  }
  @args == 0 && $promote and @args = (":full");
  @h{@args} = (1) x @args;

  $^H{charnames_full} = delete $h{':full'};
  $^H{charnames_short} = delete $h{':short'};
  $^H{charnames_scripts} = [map uc, keys %h];

  ##
  ## If utf8? warnings are enabled, and some scripts were given,
  ## see if at least we can find one letter of each script.
  ##
  if (warnings::enabled('utf8') && @{$^H{charnames_scripts}}) {
    $txt = do "unicore/Name.pl" unless $txt;

    for my $script (@{$^H{charnames_scripts}}) {
      if (not $txt =~ m/\t\t$script (?:CAPITAL |SMALL )?LETTER /) {
        warnings::warn('utf8',  "No such script: '$script'");
      }
    }
  }
} # import

# this comes actually from Unicode::UCD, but it avoids the
# overhead of loading it
sub _getcode {
    my $arg = shift;

    if ($arg =~ /^[1-9]\d*$/) {
        return $arg;
    } elsif ($arg =~ /^(?:[Uu]\+|0[xX])?([[:xdigit:]]+)$/) {
        return hex($1);
    }

    return;
}

my %viacode;

sub viacode
{
  if (@_ != 1) {
    carp "charnames::viacode() expects one argument";
    return ()
  }

  my $arg = shift;
  my $code = _getcode($arg);

  my $hex;

  if (defined $code) {
    $hex = sprintf "%04X", $arg;
  } else {
    carp("unexpected arg \"$arg\" to charnames::viacode()");
    return;
  }

  if ($code > 0x10FFFF) {
    carp sprintf "Unicode characters only allocated up to U+10FFFF (you asked for U+%X)", $hex;
    return;
  }

  return $viacode{$hex} if exists $viacode{$hex};

  $txt = do "unicore/Name.pl" unless $txt;

  if ($txt =~ m/^$hex\t\t(.+)/m) {
    return $viacode{$hex} = $1;
  } else {
    return;
  }
} # viacode

my %vianame;

sub vianame
{
  if (@_ != 1) {
    carp "charnames::vianame() expects one name argument";
    return ()
  }

  my $arg = shift;

  return chr hex $1 if $arg =~ /^U\+([0-9a-fA-F]+)$/;

  return $vianame{$arg} if exists $vianame{$arg};

  $txt = do "unicore/Name.pl" unless $txt;

  my $pos = index $txt, "\t\t$arg\n";
  if ($[ <= $pos) {
    my $posLF = rindex $txt, "\n", $pos;
    (my $code = substr $txt, $posLF + 1, 6) =~ tr/\t//d;
    return $vianame{$arg} = hex $code;

    # If $pos is at the 1st line, $posLF must be $[ - 1 (not found);
    # then $posLF + 1 equals to $[ (at the beginning of $txt).
    # Otherwise $posLF is the position of "\n";
    # then $posLF + 1 must be the position of the next to "\n"
    # (the beginning of the line).
    # substr($txt, $posLF + 1, 6) may be "0000\t\t", "00A1\t\t",
    # "10300\t", "100000", etc. So we can get the code via removing TAB.
  } else {
    return;
  }
} # vianame


1;
__END__

=head1 NAME

charnames - define character names for C<\N{named}> string literal escapes

=head1 SYNOPSIS

  use charnames ':full';
  print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";

  use charnames ':short';
  print "\N{greek:Sigma} is an upper-case sigma.\n";

  use charnames qw(cyrillic greek);
  print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";

  use charnames ":full", ":alias" => {
    e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
  };
  print "\N{e_ACUTE} is a small letter e with an acute.\n";

  use charnames ();
  print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
  printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"

=head1 DESCRIPTION

Pragma C<use charnames> supports arguments C<:full>, C<:short>, script
names and customized aliases.  If C<:full> is present, for expansion of
C<\N{CHARNAME}>, the string C<CHARNAME> is first looked up in the list of
standard Unicode character names.  If C<:short> is present, and
C<CHARNAME> has the form C<SCRIPT:CNAME>, then C<CNAME> is looked up
as a letter in script C<SCRIPT>.  If pragma C<use charnames> is used
with script name arguments, then for C<\N{CHARNAME}> the name
C<CHARNAME> is looked up as a letter in the given scripts (in the
specified order). Customized aliases are explained in L</CUSTOM ALIASES>.

For lookup of C<CHARNAME> inside a given script C<SCRIPTNAME>
this pragma looks for the names

  SCRIPTNAME CAPITAL LETTER CHARNAME
  SCRIPTNAME SMALL LETTER CHARNAME
  SCRIPTNAME LETTER CHARNAME

in the table of standard Unicode names.  If C<CHARNAME> is lowercase,
then the C<CAPITAL> variant is ignored, otherwise the C<SMALL> variant
is ignored.

Note that C<\N{...}> is compile-time, it's a special form of string
constant used inside double-quoted strings: in other words, you cannot
use variables inside the C<\N{...}>.  If you want similar run-time
functionality, use charnames::vianame().

For the C0 and C1 control characters (U+0000..U+001F, U+0080..U+009F)
as of Unicode 3.1, there are no official Unicode names but you can use
instead the ISO 6429 names (LINE FEED, ESCAPE, and so forth).  In
Unicode 3.2 (as of Perl 5.8) some naming changes take place ISO 6429
has been updated, see L</ALIASES>.  Also note that the U+UU80, U+0081,
U+0084, and U+0099 do not have names even in ISO 6429.

Since the Unicode standard uses "U+HHHH", so can you: "\N{U+263a}"
is the Unicode smiley face, or "\N{WHITE SMILING FACE}".

=head1 CUSTOM TRANSLATORS

The mechanism of translation of C<\N{...}> escapes is general and not
hardwired into F<charnames.pm>.  A module can install custom
translations (inside the scope which C<use>s the module) with the
following magic incantation:

    use charnames ();           # for $charnames::hint_bits
    sub import {
        shift;
        $^H |= $charnames::hint_bits;
        $^H{charnames} = \&translator;
    }

Here translator() is a subroutine which takes C<CHARNAME> as an
argument, and returns text to insert into the string instead of the
C<\N{CHARNAME}> escape.  Since the text to insert should be different
in C<bytes> mode and out of it, the function should check the current
state of C<bytes>-flag as in:

    use bytes ();                       # for $bytes::hint_bits
    sub translator {
        if ($^H & $bytes::hint_bits) {
            return bytes_translator(@_);
        }
        else {
            return utf8_translator(@_);
        }
    }

=head1 CUSTOM ALIASES

This version of charnames supports three mechanisms of adding local
or customized aliases to standard Unicode naming conventions (:full)

=head2 Anonymous hashes

    use charnames ":full", ":alias" => {
        e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
        };
    my $str = "\N{e_ACUTE}";

=head2 Alias file

    use charnames ":full", ":alias" => "pro";

    will try to read "unicore/pro_alias.pl" from the @INC path. This
    file should return a list in plain perl:

    (
    A_GRAVE         => "LATIN CAPITAL LETTER A WITH GRAVE",
    A_CIRCUM        => "LATIN CAPITAL LETTER A WITH CIRCUMFLEX",
    A_DIAERES       => "LATIN CAPITAL LETTER A WITH DIAERESIS",
    A_TILDE         => "LATIN CAPITAL LETTER A WITH TILDE",
    A_BREVE         => "LATIN CAPITAL LETTER A WITH BREVE",
    A_RING          => "LATIN CAPITAL LETTER A WITH RING ABOVE",
    A_MACRON        => "LATIN CAPITAL LETTER A WITH MACRON",
    );

=head2 Alias shortcut

    use charnames ":alias" => ":pro";

    works exactly the same as the alias pairs, only this time,
    ":full" is inserted automatically as first argument (if no
    other argument is given).

=head1 charnames::viacode(code)

Returns the full name of the character indicated by the numeric code.
The example

    print charnames::viacode(0x2722);

prints "FOUR TEARDROP-SPOKED ASTERISK".

Returns undef if no name is known for the code.

This works only for the standard names, and does not yet apply
to custom translators.

Notice that the name returned for of U+FEFF is "ZERO WIDTH NO-BREAK
SPACE", not "BYTE ORDER MARK".

=head1 charnames::vianame(name)

Returns the code point indicated by the name.
The example

    printf "%04X", charnames::vianame("FOUR TEARDROP-SPOKED ASTERISK");

prints "2722".

Returns undef if the name is unknown.

This works only for the standard names, and does not yet apply
to custom translators.

=head1 ALIASES

A few aliases have been defined for convenience: instead of having
to use the official names

    LINE FEED (LF)
    FORM FEED (FF)
    CARRIAGE RETURN (CR)
    NEXT LINE (NEL)

(yes, with parentheses) one can use

    LINE FEED
    FORM FEED
    CARRIAGE RETURN
    NEXT LINE
    LF
    FF
    CR
    NEL

One can also use

    BYTE ORDER MARK
    BOM

and

    ZWNJ
    ZWJ

for ZERO WIDTH NON-JOINER and ZERO WIDTH JOINER.

For backward compatibility one can use the old names for
certain C0 and C1 controls

    old                         new

    HORIZONTAL TABULATION       CHARACTER TABULATION
    VERTICAL TABULATION         LINE TABULATION
    FILE SEPARATOR              INFORMATION SEPARATOR FOUR
    GROUP SEPARATOR             INFORMATION SEPARATOR THREE
    RECORD SEPARATOR            INFORMATION SEPARATOR TWO
    UNIT SEPARATOR              INFORMATION SEPARATOR ONE
    PARTIAL LINE DOWN           PARTIAL LINE FORWARD
    PARTIAL LINE UP             PARTIAL LINE BACKWARD

but the old names in addition to giving the character
will also give a warning about being deprecated.

=head1 ILLEGAL CHARACTERS

If you ask by name for a character that does not exist, a warning is
given and the Unicode I<replacement character> "\x{FFFD}" is returned.

If you ask by code for a character that does not exist, no warning is
given and C<undef> is returned.  (Though if you ask for a code point
past U+10FFFF you do get a warning.)

=head1 BUGS

Since evaluation of the translation function happens in a middle of
compilation (of a string literal), the translation function should not
do any C<eval>s or C<require>s.  This restriction should be lifted in
a future version of Perl.

=cut
Revision:	1.1
Committed:	Thu Jun 30 14:27:08 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	package charnames;
2			use strict;
3			use warnings;
4			use Carp;
5			use File::Spec;
6			our $VERSION = '1.04';
7
8			use bytes (); # for $bytes::hint_bits
9			$charnames::hint_bits = 0x20000; # HINT_LOCALIZE_HH
10
11			my %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
30			my %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
42			my %alias3 = (
43			# User defined aliasses. Even more convenient :)
44			);
45			my $txt;
46
47			sub alias (@)
48			{
49			@_ or return %alias3;
50			my $alias = ref $_[0] ? $_[0] : { @_ };
51			@alias3{keys %$alias} = values %$alias;
52			} # alias
53
54			sub alias_file ($)
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
78			sub 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
179			sub 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
241			# this comes actually from Unicode::UCD, but it avoids the
242			# overhead of loading it
243			sub _getcode {
244			my $arg = shift;
245
246			if ($arg =~ /^[1-9]\d*$/) {
247			return $arg;
248			} elsif ($arg =~ /^(?:[Uu]\+\|0[xX])?([[:xdigit:]]+)$/) {
249			return hex($1);
250			}
251
252			return;
253			}
254
255			my %viacode;
256
257			sub viacode
258			{
259			if (@_ != 1) {
260			carp "charnames::viacode() expects one argument";
261			return ()
262			}
263
264			my $arg = shift;
265			my $code = _getcode($arg);
266
267			my $hex;
268
269			if (defined $code) {
270			$hex = sprintf "%04X", $arg;
271			} else {
272			carp("unexpected arg \"$arg\" to charnames::viacode()");
273			return;
274			}
275
276			if ($code > 0x10FFFF) {
277			carp sprintf "Unicode characters only allocated up to U+10FFFF (you asked for U+%X)", $hex;
278			return;
279			}
280
281			return $viacode{$hex} if exists $viacode{$hex};
282
283			$txt = do "unicore/Name.pl" unless $txt;
284
285			if ($txt =~ m/^$hex\t\t(.+)/m) {
286			return $viacode{$hex} = $1;
287			} else {
288			return;
289			}
290			} # viacode
291
292			my %vianame;
293
294			sub vianame
295			{
296			if (@_ != 1) {
297			carp "charnames::vianame() expects one name argument";
298			return ()
299			}
300
301			my $arg = shift;
302
303			return chr hex $1 if $arg =~ /^U\+([0-9a-fA-F]+)$/;
304
305			return $vianame{$arg} if exists $vianame{$arg};
306
307			$txt = do "unicore/Name.pl" unless $txt;
308
309			my $pos = index $txt, "\t\t$arg\n";
310			if ($[ <= $pos) {
311			my $posLF = rindex $txt, "\n", $pos;
312			(my $code = substr $txt, $posLF + 1, 6) =~ tr/\t//d;
313			return $vianame{$arg} = hex $code;
314
315			# If $pos is at the 1st line, $posLF must be $[ - 1 (not found);
316			# then $posLF + 1 equals to $[ (at the beginning of $txt).
317			# Otherwise $posLF is the position of "\n";
318			# then $posLF + 1 must be the position of the next to "\n"
319			# (the beginning of the line).
320			# substr($txt, $posLF + 1, 6) may be "0000\t\t", "00A1\t\t",
321			# "10300\t", "100000", etc. So we can get the code via removing TAB.
322			} else {
323			return;
324			}
325			} # vianame
326
327
328			1;
329			__END__
330
331			=head1 NAME
332
333			charnames - define character names for C<\N{named}> string literal escapes
334
335			=head1 SYNOPSIS
336
337			use charnames ':full';
338			print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";
339
340			use charnames ':short';
341			print "\N{greek:Sigma} is an upper-case sigma.\n";
342
343			use charnames qw(cyrillic greek);
344			print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";
345
346			use charnames ":full", ":alias" => {
347			e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
348			};
349			print "\N{e_ACUTE} is a small letter e with an acute.\n";
350
351			use charnames ();
352			print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
353			printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"
354
355			=head1 DESCRIPTION
356
357			Pragma C<use charnames> supports arguments C<:full>, C<:short>, script
358			names and customized aliases. If C<:full> is present, for expansion of
359			C<\N{CHARNAME}>, the string C<CHARNAME> is first looked up in the list of
360			standard Unicode character names. If C<:short> is present, and
361			C<CHARNAME> has the form C<SCRIPT:CNAME>, then C<CNAME> is looked up
362			as a letter in script C<SCRIPT>. If pragma C<use charnames> is used
363			with script name arguments, then for C<\N{CHARNAME}> the name
364			C<CHARNAME> is looked up as a letter in the given scripts (in the
365			specified order). Customized aliases are explained in L</CUSTOM ALIASES>.
366
367			For lookup of C<CHARNAME> inside a given script C<SCRIPTNAME>
368			this pragma looks for the names
369
370			SCRIPTNAME CAPITAL LETTER CHARNAME
371			SCRIPTNAME SMALL LETTER CHARNAME
372			SCRIPTNAME LETTER CHARNAME
373
374			in the table of standard Unicode names. If C<CHARNAME> is lowercase,
375			then the C<CAPITAL> variant is ignored, otherwise the C<SMALL> variant
376			is ignored.
377
378			Note that C<\N{...}> is compile-time, it's a special form of string
379			constant used inside double-quoted strings: in other words, you cannot
380			use variables inside the C<\N{...}>. If you want similar run-time
381			functionality, use charnames::vianame().
382
383			For the C0 and C1 control characters (U+0000..U+001F, U+0080..U+009F)
384			as of Unicode 3.1, there are no official Unicode names but you can use
385			instead the ISO 6429 names (LINE FEED, ESCAPE, and so forth). In
386			Unicode 3.2 (as of Perl 5.8) some naming changes take place ISO 6429
387			has been updated, see L</ALIASES>. Also note that the U+UU80, U+0081,
388			U+0084, and U+0099 do not have names even in ISO 6429.
389
390			Since the Unicode standard uses "U+HHHH", so can you: "\N{U+263a}"
391			is the Unicode smiley face, or "\N{WHITE SMILING FACE}".
392
393			=head1 CUSTOM TRANSLATORS
394
395			The mechanism of translation of C<\N{...}> escapes is general and not
396			hardwired into F<charnames.pm>. A module can install custom
397			translations (inside the scope which C<use>s the module) with the
398			following magic incantation:
399
400			use charnames (); # for $charnames::hint_bits
401			sub import {
402			shift;
403			$^H \|= $charnames::hint_bits;
404			$^H{charnames} = \&translator;
405			}
406
407			Here translator() is a subroutine which takes C<CHARNAME> as an
408			argument, and returns text to insert into the string instead of the
409			C<\N{CHARNAME}> escape. Since the text to insert should be different
410			in C<bytes> mode and out of it, the function should check the current
411			state of C<bytes>-flag as in:
412
413			use bytes (); # for $bytes::hint_bits
414			sub translator {
415			if ($^H & $bytes::hint_bits) {
416			return bytes_translator(@_);
417			}
418			else {
419			return utf8_translator(@_);
420			}
421			}
422
423			=head1 CUSTOM ALIASES
424
425			This version of charnames supports three mechanisms of adding local
426			or customized aliases to standard Unicode naming conventions (:full)
427
428			=head2 Anonymous hashes
429
430			use charnames ":full", ":alias" => {
431			e_ACUTE => "LATIN SMALL LETTER E WITH ACUTE",
432			};
433			my $str = "\N{e_ACUTE}";
434
435			=head2 Alias file
436
437			use charnames ":full", ":alias" => "pro";
438
439			will try to read "unicore/pro_alias.pl" from the @INC path. This
440			file should return a list in plain perl:
441
442			(
443			A_GRAVE => "LATIN CAPITAL LETTER A WITH GRAVE",
444			A_CIRCUM => "LATIN CAPITAL LETTER A WITH CIRCUMFLEX",
445			A_DIAERES => "LATIN CAPITAL LETTER A WITH DIAERESIS",
446			A_TILDE => "LATIN CAPITAL LETTER A WITH TILDE",
447			A_BREVE => "LATIN CAPITAL LETTER A WITH BREVE",
448			A_RING => "LATIN CAPITAL LETTER A WITH RING ABOVE",
449			A_MACRON => "LATIN CAPITAL LETTER A WITH MACRON",
450			);
451
452			=head2 Alias shortcut
453
454			use charnames ":alias" => ":pro";
455
456			works exactly the same as the alias pairs, only this time,
457			":full" is inserted automatically as first argument (if no
458			other argument is given).
459
460			=head1 charnames::viacode(code)
461
462			Returns the full name of the character indicated by the numeric code.
463			The example
464
465			print charnames::viacode(0x2722);
466
467			prints "FOUR TEARDROP-SPOKED ASTERISK".
468
469			Returns undef if no name is known for the code.
470
471			This works only for the standard names, and does not yet apply
472			to custom translators.
473
474			Notice that the name returned for of U+FEFF is "ZERO WIDTH NO-BREAK
475			SPACE", not "BYTE ORDER MARK".
476
477			=head1 charnames::vianame(name)
478
479			Returns the code point indicated by the name.
480			The example
481
482			printf "%04X", charnames::vianame("FOUR TEARDROP-SPOKED ASTERISK");
483
484			prints "2722".
485
486			Returns undef if the name is unknown.
487
488			This works only for the standard names, and does not yet apply
489			to custom translators.
490
491			=head1 ALIASES
492
493			A few aliases have been defined for convenience: instead of having
494			to use the official names
495
496			LINE FEED (LF)
497			FORM FEED (FF)
498			CARRIAGE RETURN (CR)
499			NEXT LINE (NEL)
500
501			(yes, with parentheses) one can use
502
503			LINE FEED
504			FORM FEED
505			CARRIAGE RETURN
506			NEXT LINE
507			LF
508			FF
509			CR
510			NEL
511
512			One can also use
513
514			BYTE ORDER MARK
515			BOM
516
517			and
518
519			ZWNJ
520			ZWJ
521
522			for ZERO WIDTH NON-JOINER and ZERO WIDTH JOINER.
523
524			For backward compatibility one can use the old names for
525			certain C0 and C1 controls
526
527			old new
528
529			HORIZONTAL TABULATION CHARACTER TABULATION
530			VERTICAL TABULATION LINE TABULATION
531			FILE SEPARATOR INFORMATION SEPARATOR FOUR
532			GROUP SEPARATOR INFORMATION SEPARATOR THREE
533			RECORD SEPARATOR INFORMATION SEPARATOR TWO
534			UNIT SEPARATOR INFORMATION SEPARATOR ONE
535			PARTIAL LINE DOWN PARTIAL LINE FORWARD
536			PARTIAL LINE UP PARTIAL LINE BACKWARD
537
538			but the old names in addition to giving the character
539			will also give a warning about being deprecated.
540
541			=head1 ILLEGAL CHARACTERS
542
543			If you ask by name for a character that does not exist, a warning is
544			given and the Unicode I<replacement character> "\x{FFFD}" is returned.
545
546			If you ask by code for a character that does not exist, no warning is
547			given and C<undef> is returned. (Though if you ask for a code point
548			past U+10FFFF you do get a warning.)
549
550			=head1 BUGS
551
552			Since evaluation of the translation function happens in a middle of
553			compilation (of a string literal), the translation function should not
554			do any C<eval>s or C<require>s. This restriction should be lifted in
555			a future version of Perl.
556
557			=cut