[perl5.git] / lib / charnames.pm

package charnames;
use strict;
use warnings;
use Carp;
our $VERSION = '1.01';

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

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 $txt;

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

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

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 %h;
  @h{@_} = (1) x @_;

  $^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'");
          }
      }
  }
}

require Unicode::UCD; # for Unicode::UCD::_getcode()

my %viacode;

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

    my $arg = shift;
    my $code = Unicode::UCD::_getcode($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;
    }
}

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;
    }
}


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";

  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> and
script names.  If C<:full> is present, for expansion of
C<\N{CHARNAME}> string C<CHARNAME> is first looked in the list of
standard Unicode names of chars.  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).

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 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
Commit	Line	Data
423cee85	1	package charnames;
b177ca84 JF	2	use strict;
	3	use warnings;
	4	use Carp;
	5	our $VERSION = '1.01';
b75c8c73	6
d5448623 GS	7	use bytes (); # for $bytes::hint_bits
d5448623 GS	8	$charnames::hint_bits = 0x20000;
423cee85	9
52ea3e69 JH	10	my %alias1 = (
	11	# Icky 3.2 names with parentheses.
	12	'LINE FEED' => 'LINE FEED (LF)',
	13	'FORM FEED' => 'FORM FEED (FF)',
	14	'CARRIAGE RETURN' => 'CARRIAGE RETURN (CR)',
	15	'NEXT LINE' => 'NEXT LINE (NEL)',
	16	# Convenience.
	17	'LF' => 'LINE FEED (LF)',
	18	'FF' => 'FORM FEED (FF)',
eb380778	19	'CR' => 'CARRIAGE RETURN (CR)',
51e9e896	20	'NEL' => 'NEXT LINE (NEL)',
24b5d5cc JH	21	# More convenience. For futher convencience,
	22	# it is suggested some way using using the NamesList
	23	# aliases is implemented.
	24	'ZWNJ' => 'ZERO WIDTH NON-JOINER',
	25	'ZWJ' => 'ZERO WIDTH JOINER',
52ea3e69 JH	26	'BOM' => 'BYTE ORDER MARK',
	27	);
	28
	29	my %alias2 = (
	30	# Pre-3.2 compatibility (only for the first 256 characters).
	31	'HORIZONTAL TABULATION' => 'CHARACTER TABULATION',
	32	'VERTICAL TABULATION' => 'LINE TABULATION',
	33	'FILE SEPARATOR' => 'INFORMATION SEPARATOR FOUR',
	34	'GROUP SEPARATOR' => 'INFORMATION SEPARATOR THREE',
	35	'RECORD SEPARATOR' => 'INFORMATION SEPARATOR TWO',
	36	'UNIT SEPARATOR' => 'INFORMATION SEPARATOR ONE',
	37	'PARTIAL LINE DOWN' => 'PARTIAL LINE FORWARD',
	38	'PARTIAL LINE UP' => 'PARTIAL LINE BACKWARD',
	39	);
	40
423cee85 JH	41	my $txt;
	42
	43	# This is not optimized in any way yet
b177ca84 JF	44	sub charnames
	45	{
	46	my $name = shift;
	47
52ea3e69 JH	48	if (exists $alias1{$name}) {
	49	$name = $alias1{$name};
	50	}
	51	if (exists $alias2{$name}) {
	52	require warnings;
	53	warnings::warnif('deprecated', qq{Unicode character name "$name" is deprecated, use "$alias2{$name}" instead});
	54	$name = $alias2{$name};
	55	}
b177ca84	56
52ea3e69	57	my $ord;
423cee85	58	my @off;
52ea3e69 JH	59	my $fname;
	60
	61	if ($name eq "BYTE ORDER MARK") {
	62	$fname = $name;
d7d589a8	63	$ord = 0xFEFF;
52ea3e69 JH	64	} else {
	65	## Suck in the code/name list as a big string.
	66	## Lines look like:
	67	## "0052\t\tLATIN CAPITAL LETTER R\n"
	68	$txt = do "unicore/Name.pl" unless $txt;
b177ca84	69
52ea3e69 JH	70	## @off will hold the index into the code/name string of the start and
	71	## end of the name as we find it.
	72
	73	## If :full, look for the the name exactly
	74	if ($^H{charnames_full} and $txt =~ /\t\t\Q$name\E$/m) {
	75	@off = ($-[0], $+[0]);
423cee85	76	}
b177ca84	77
52ea3e69 JH	78	## If we didn't get above, and :short allowed, look for the short name.
	79	## The short name is like "greek:Sigma"
	80	unless (@off) {
	81	if ($^H{charnames_short} and $name =~ /^(.+?):(.+)/s) {
	82	my ($script, $cname) = ($1,$2);
	83	my $case = ( $cname =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL");
	84	if ($txt =~ m/\t\t\U$script\E (?:$case )?LETTER \U\Q$cname\E$/m) {
	85	@off = ($-[0], $+[0]);
	86	}
	87	}
	88	}
	89
	90	## If we still don't have it, check for the name among the loaded
	91	## scripts.
	92	if (not @off)
b177ca84	93	{
52ea3e69 JH	94	my $case = ( $name =~ /[[:upper:]]/ ? "CAPITAL" : "SMALL");
	95	for my $script ( @{$^H{charnames_scripts}} )
	96	{
	97	if ($txt =~ m/\t\t$script (?:$case )?LETTER \U\Q$name\E$/m) {
	98	@off = ($-[0], $+[0]);
	99	last;
	100	}
	101	}
b177ca84	102	}
52ea3e69 JH	103
	104	## If we don't have it by now, give up.
	105	unless (@off) {
	106	carp "Unknown charname '$name'";
	107	return "\x{FFFD}";
	108	}
	109
	110	##
	111	## Now know where in the string the name starts.
274085e3	112	## The code, in hex, is before that.
52ea3e69 JH	113	##
	114	## The code can be 4-6 characters long, so we've got to sort of
	115	## go look for it, just after the newline that comes before $off[0].
	116	##
	117	## This would be much easier if unicore/Name.pl had info in
	118	## a name/code order, instead of code/name order.
	119	##
	120	## The +1 after the rindex() is to skip past the newline we're finding,
	121	## or, if the rindex() fails, to put us to an offset of zero.
	122	##
	123	my $hexstart = rindex($txt, "\n", $off[0]) + 1;
	124
	125	## we know where it starts, so turn into number -
	126	## the ordinal for the char.
	127	$ord = hex substr($txt, $hexstart, $off[0] - $hexstart);
423cee85	128	}
b177ca84	129
d5448623	130	if ($^H & $bytes::hint_bits) { # "use bytes" in effect?
8058d7ab	131	use bytes;
d41ff1b8	132	return chr $ord if $ord <= 255;
f0175764	133	my $hex = sprintf "%04x", $ord;
52ea3e69 JH	134	if (not defined $fname) {
	135	$fname = substr $txt, $off[0] + 2, $off[1] - $off[0] - 2;
	136	}
f0175764	137	croak "Character 0x$hex with name '$fname' is above 0xFF";
423cee85	138	}
f0175764	139
52ea3e69	140	no warnings 'utf8'; # allow even illegal characters
bfa383d6	141	return pack "U", $ord;
423cee85 JH	142	}
423cee85 JH	143
b177ca84 JF	144	sub import
	145	{
	146	shift; ## ignore class name
	147
	148	if (not @_)
	149	{
	150	carp("`use charnames' needs explicit imports list");
	151	}
d5448623	152	$^H \|= $charnames::hint_bits;
423cee85	153	$^H{charnames} = \&charnames ;
b177ca84 JF	154
	155	##
	156	## fill %h keys with our @_ args.
	157	##
423cee85 JH	158	my %h;
423cee85 JH	159	@h{@_} = (1) x @_;
b177ca84	160
423cee85 JH	161	$^H{charnames_full} = delete $h{':full'};
	162	$^H{charnames_short} = delete $h{':short'};
	163	$^H{charnames_scripts} = [map uc, keys %h];
b177ca84 JF	164
	165	##
	166	## If utf8? warnings are enabled, and some scripts were given,
	167	## see if at least we can find one letter of each script.
	168	##
	169	if (warnings::enabled('utf8') && @{$^H{charnames_scripts}})
	170	{
	171	$txt = do "unicore/Name.pl" unless $txt;
	172
	173	for my $script (@{$^H{charnames_scripts}})
	174	{
	175	if (not $txt =~ m/\t\t$script (?:CAPITAL \|SMALL )?LETTER /) {
	176	warnings::warn('utf8', "No such script: '$script'");
	177	}
	178	}
bd62941a	179	}
423cee85 JH	180	}
423cee85 JH	181
f0175764 JH	182	require Unicode::UCD; # for Unicode::UCD::_getcode()
f0175764 JH	183
4e2cda5d JH	184	my %viacode;
4e2cda5d JH	185
b177ca84 JF	186	sub viacode
	187	{
	188	if (@_ != 1) {
274085e3	189	carp "charnames::viacode() expects one argument";
b177ca84 JF	190	return ()
b177ca84 JF	191	}
f0175764	192
b177ca84	193	my $arg = shift;
f0175764	194	my $code = Unicode::UCD::_getcode($arg);
b177ca84 JF	195
b177ca84 JF	196	my $hex;
f0175764 JH	197
f0175764 JH	198	if (defined $code) {
b177ca84 JF	199	$hex = sprintf "%04X", $arg;
	200	} else {
	201	carp("unexpected arg \"$arg\" to charnames::viacode()");
daf0d493	202	return;
b177ca84 JF	203	}
b177ca84 JF	204
f0175764	205	if ($code > 0x10FFFF) {
00d835f2	206	carp sprintf "Unicode characters only allocated up to U+10FFFF (you asked for U+%X)", $hex;
11881cb4	207	return;
f0175764 JH	208	}
f0175764 JH	209
4e2cda5d JH	210	return $viacode{$hex} if exists $viacode{$hex};
4e2cda5d JH	211
b177ca84 JF	212	$txt = do "unicore/Name.pl" unless $txt;
	213
	214	if ($txt =~ m/^$hex\t\t(.+)/m) {
4e2cda5d	215	return $viacode{$hex} = $1;
b177ca84	216	} else {
11881cb4	217	return;
daf0d493 JH	218	}
	219	}
	220
4e2cda5d JH	221	my %vianame;
4e2cda5d JH	222
daf0d493 JH	223	sub vianame
	224	{
	225	if (@_ != 1) {
	226	carp "charnames::vianame() expects one name argument";
	227	return ()
	228	}
	229
	230	my $arg = shift;
	231
dbc0d4f2 JH	232	return chr hex $1 if $arg =~ /^U\+([0-9a-fA-F]+)$/;
dbc0d4f2 JH	233
4e2cda5d JH	234	return $vianame{$arg} if exists $vianame{$arg};
4e2cda5d JH	235
daf0d493 JH	236	$txt = do "unicore/Name.pl" unless $txt;
daf0d493 JH	237
94ec6410 TS	238	my $pos = index $txt, "\t\t$arg\n";
	239	if ($[ <= $pos) {
	240	my $posLF = rindex $txt, "\n", $pos;
	241	(my $code = substr $txt, $posLF + 1, 6) =~ tr/\t//d;
	242	return $vianame{$arg} = hex $code;
	243
	244	# If $pos is at the 1st line, $posLF must be $[ - 1 (not found);
	245	# then $posLF + 1 equals to $[ (at the beginning of $txt).
	246	# Otherwise $posLF is the position of "\n";
	247	# then $posLF + 1 must be the position of the next to "\n"
	248	# (the beginning of the line).
	249	# substr($txt, $posLF + 1, 6) may be "0000\t\t", "00A1\t\t",
	250	# "10300\t", "100000", etc. So we can get the code via removing TAB.
daf0d493 JH	251	} else {
daf0d493 JH	252	return;
b177ca84 JF	253	}
	254	}
	255
423cee85 JH	256
	257	1;
	258	__END__
	259
	260	=head1 NAME
	261
274085e3	262	charnames - define character names for C<\N{named}> string literal escapes
423cee85 JH	263
	264	=head1 SYNOPSIS
	265
	266	use charnames ':full';
4a2d328f	267	print "\N{GREEK SMALL LETTER SIGMA} is called sigma.\n";
423cee85 JH	268
423cee85 JH	269	use charnames ':short';
4a2d328f	270	print "\N{greek:Sigma} is an upper-case sigma.\n";
423cee85 JH	271
423cee85 JH	272	use charnames qw(cyrillic greek);
4a2d328f	273	print "\N{sigma} is Greek sigma, and \N{be} is Cyrillic b.\n";
423cee85	274
a23c04e4 JH	275	print charnames::viacode(0x1234); # prints "ETHIOPIC SYLLABLE SEE"
a23c04e4 JH	276	printf "%04X", charnames::vianame("GOTHIC LETTER AHSA"); # prints "10330"
b177ca84	277
423cee85 JH	278	=head1 DESCRIPTION
	279
	280	Pragma C<use charnames> supports arguments C<:full>, C<:short> and
	281	script names. If C<:full> is present, for expansion of
a191c821	282	C<\N{CHARNAME}> string C<CHARNAME> is first looked in the list of
423cee85 JH	283	standard Unicode names of chars. If C<:short> is present, and
	284	C<CHARNAME> has the form C<SCRIPT:CNAME>, then C<CNAME> is looked up
	285	as a letter in script C<SCRIPT>. If pragma C<use charnames> is used
a191c821	286	with script name arguments, then for C<\N{CHARNAME}> the name
423cee85 JH	287	C<CHARNAME> is looked up as a letter in the given scripts (in the
	288	specified order).
	289
	290	For lookup of C<CHARNAME> inside a given script C<SCRIPTNAME>
d5448623	291	this pragma looks for the names
423cee85 JH	292
	293	SCRIPTNAME CAPITAL LETTER CHARNAME
	294	SCRIPTNAME SMALL LETTER CHARNAME
	295	SCRIPTNAME LETTER CHARNAME
	296
	297	in the table of standard Unicode names. If C<CHARNAME> is lowercase,
daf0d493 JH	298	then the C<CAPITAL> variant is ignored, otherwise the C<SMALL> variant
	299	is ignored.
	300
	301	Note that C<\N{...}> is compile-time, it's a special form of string
	302	constant used inside double-quoted strings: in other words, you cannot
4e2cda5d	303	use variables inside the C<\N{...}>. If you want similar run-time
daf0d493	304	functionality, use charnames::vianame().
423cee85	305
301a3cda	306	For the C0 and C1 control characters (U+0000..U+001F, U+0080..U+009F)
dbc0d4f2 JH	307	as of Unicode 3.1, there are no official Unicode names but you can use
	308	instead the ISO 6429 names (LINE FEED, ESCAPE, and so forth). In
	309	Unicode 3.2 (as of Perl 5.8) some naming changes take place ISO 6429
	310	has been updated, see L</ALIASES>. Also note that the U+UU80, U+0081,
	311	U+0084, and U+0099 do not have names even in ISO 6429.
	312
	313	Since the Unicode standard uses "U+HHHH", so can you: "\N{U+263a}"
	314	is the Unicode smiley face, or "\N{WHITE SMILING FACE}".
301a3cda	315
423cee85 JH	316	=head1 CUSTOM TRANSLATORS
423cee85 JH	317
d5448623	318	The mechanism of translation of C<\N{...}> escapes is general and not
423cee85	319	hardwired into F<charnames.pm>. A module can install custom
d5448623	320	translations (inside the scope which C<use>s the module) with the
423cee85 JH	321	following magic incantation:
423cee85 JH	322
d5448623 GS	323	use charnames (); # for $charnames::hint_bits
	324	sub import {
	325	shift;
	326	$^H \|= $charnames::hint_bits;
	327	$^H{charnames} = \&translator;
	328	}
423cee85 JH	329
	330	Here translator() is a subroutine which takes C<CHARNAME> as an
	331	argument, and returns text to insert into the string instead of the
4a2d328f	332	C<\N{CHARNAME}> escape. Since the text to insert should be different
d5448623 GS	333	in C<bytes> mode and out of it, the function should check the current
	334	state of C<bytes>-flag as in:
	335
	336	use bytes (); # for $bytes::hint_bits
	337	sub translator {
	338	if ($^H & $bytes::hint_bits) {
	339	return bytes_translator(@_);
	340	}
	341	else {
	342	return utf8_translator(@_);
	343	}
423cee85	344	}
423cee85	345
b177ca84 JF	346	=head1 charnames::viacode(code)
	347
	348	Returns the full name of the character indicated by the numeric code.
	349	The example
	350
	351	print charnames::viacode(0x2722);
	352
	353	prints "FOUR TEARDROP-SPOKED ASTERISK".
	354
daf0d493 JH	355	Returns undef if no name is known for the code.
daf0d493 JH	356
274085e3	357	This works only for the standard names, and does not yet apply
daf0d493 JH	358	to custom translators.
daf0d493 JH	359
274085e3 PN	360	Notice that the name returned for of U+FEFF is "ZERO WIDTH NO-BREAK
	361	SPACE", not "BYTE ORDER MARK".
	362
eb6a2339	363	=head1 charnames::vianame(name)
daf0d493 JH	364
	365	Returns the code point indicated by the name.
	366	The example
	367
	368	printf "%04X", charnames::vianame("FOUR TEARDROP-SPOKED ASTERISK");
	369
	370	prints "2722".
	371
eb6a2339	372	Returns undef if the name is unknown.
b177ca84	373
eb6a2339	374	This works only for the standard names, and does not yet apply
b177ca84 JF	375	to custom translators.
b177ca84 JF	376
52ea3e69 JH	377	=head1 ALIASES
	378
	379	A few aliases have been defined for convenience: instead of having
	380	to use the official names
	381
	382	LINE FEED (LF)
	383	FORM FEED (FF)
	384	CARRIAGE RETURN (CR)
	385	NEXT LINE (NEL)
	386
	387	(yes, with parentheses) one can use
	388
	389	LINE FEED
	390	FORM FEED
	391	CARRIAGE RETURN
	392	NEXT LINE
	393	LF
	394	FF
	395	CR
	396	NEL
	397
	398	One can also use
	399
	400	BYTE ORDER MARK
	401	BOM
	402
24b5d5cc JH	403	and
	404
	405	ZWNJ
	406	ZWJ
	407
	408	for ZERO WIDTH NON-JOINER and ZERO WIDTH JOINER.
52ea3e69 JH	409
	410	For backward compatibility one can use the old names for
	411	certain C0 and C1 controls
	412
	413	old new
	414
	415	HORIZONTAL TABULATION CHARACTER TABULATION
	416	VERTICAL TABULATION LINE TABULATION
	417	FILE SEPARATOR INFORMATION SEPARATOR FOUR
	418	GROUP SEPARATOR INFORMATION SEPARATOR THREE
	419	RECORD SEPARATOR INFORMATION SEPARATOR TWO
	420	UNIT SEPARATOR INFORMATION SEPARATOR ONE
	421	PARTIAL LINE DOWN PARTIAL LINE FORWARD
	422	PARTIAL LINE UP PARTIAL LINE BACKWARD
	423
	424	but the old names in addition to giving the character
	425	will also give a warning about being deprecated.
	426
f0175764 JH	427	=head1 ILLEGAL CHARACTERS
f0175764 JH	428
00d835f2 JH	429	If you ask by name for a character that does not exist, a warning is
	430	given and the Unicode I<replacement character> "\x{FFFD}" is returned.
	431
	432	If you ask by code for a character that does not exist, no warning is
	433	given and C<undef> is returned. (Though if you ask for a code point
	434	past U+10FFFF you do get a warning.)
f0175764	435
423cee85 JH	436	=head1 BUGS
	437
	438	Since evaluation of the translation function happens in a middle of
	439	compilation (of a string literal), the translation function should not
	440	do any C<eval>s or C<require>s. This restriction should be lifted in
	441	a future version of Perl.
	442
	443	=cut