Code Index:

package Encode::Alias
__END__
EOF

NAME

Encode::Alias - alias definitions to encodings

SYNOPSIS

  use Encode;
  use Encode::Alias;
  define_alias( newName => ENCODING);

DESCRIPTION

Allows newName to be used as an alias for ENCODING. ENCODING may be either the name of an encoding or an encoding object (as described in Encode).

Currently newName can be specified in the following ways:

As a simple string.

As a qr// compiled regular expression, e.g.:

  define_alias( qr/^iso8859-(\d+)$/i => '"iso-8859-$1"' );

In this case, if ENCODING is not a reference, it is eval-ed in order to allow $1 etc. to be substituted. The example is one way to alias names as used in X11 fonts to the MIME names for the iso-8859-* family. Note the double quotes inside the single quotes.

(or, you don't have to do this yourself because this example is predefined)

If you are using a regex here, you have to use the quotes as shown or it won't work. Also note that regex handling is tricky even for the experienced. Use this feature with caution.

As a code reference, e.g.:

  define_alias( sub {shift =~ /^iso8859-(\d+)$/i ? "iso-8859-$1" : undef } );

The same effect as the example above in a different way. The coderef takes the alias name as an argument and returns a canonical name on success or undef if not. Note the second argument is not required. Use this with even more caution than the regex version.

Changes in code reference aliasing

As of Encode 1.87, the older form

  define_alias( sub { return  /^iso8859-(\d+)$/i ? "iso-8859-$1" : undef } );

no longer works.

Encode up to 1.86 internally used "local $_" to implement ths older form. But consider the code below;

  use Encode;
  $_ = "eeeee" ;
  while (/(e)/g) {
    my $utf = decode('aliased-encoding-name', $1);
    print "position:",pos,"\n";
  }

Prior to Encode 1.86 this fails because of "local $_".

Alias overloading

You can override predefined aliases by simply applying define_alias(). The new alias is always evaluated first, and when necessary, define_alias() flushes the internal cache to make the new definition available.

  # redirect SHIFT_JIS to MS/IBM Code Page 932, which is a
  # superset of SHIFT_JIS

  define_alias( qr/shift.*jis$/i  => '"cp932"' );
  define_alias( qr/sjis$/i        => '"cp932"' );

If you want to zap all predefined aliases, you can use

  Encode::Alias->undef_aliases;

to do so. And

  Encode::Alias->init_aliases;

gets the factory settings back.

package Encode::Alias; use strict; use warnings; no warnings 'redefine'; our $VERSION = do { my @r = ( q$Revision: 2.12 $ =~ /\d+/g ); sprintf "%d." . "%02d" x $#r, @r }; sub DEBUG () { 0 } use base qw(Exporter); # Public, encouraged API is exported by default our @EXPORT = qw ( define_alias find_alias ); our @Alias; # ordered matching list our %Alias; # cached known aliases sub find_alias { require Encode; my $class = shift; my $find = shift; unless ( exists $Alias{$find} ) { $Alias{$find} = undef; # Recursion guard for ( my $i = 0 ; $i < @Alias ; $i += 2 ) { my $alias = $Alias[$i]; my $val = $Alias[ $i + 1 ]; my $new; if ( ref($alias) eq 'Regexp' && $find =~ $alias ) { DEBUG and warn "eval $val"; $new = eval $val; DEBUG and $@ and warn "$val, $@"; } elsif ( ref($alias) eq 'CODE' ) { DEBUG and warn "$alias", "->", "($find)"; $new = $alias->($find); } elsif ( lc($find) eq lc($alias) ) { $new = $val; } if ( defined($new) ) { next if $new eq $find; # avoid (direct) recursion on bugs DEBUG and warn "$alias, $new"; my $enc = ( ref($new) ) ? $new : Encode::find_encoding($new); if ($enc) { $Alias{$find} = $enc; last; } } } # case insensitive search when canonical is not in all lowercase # RT ticket #7835 unless ( $Alias{$find} ) { my $lcfind = lc($find); for my $name ( keys %Encode::Encoding, keys %Encode::ExtModule ) { $lcfind eq lc($name) or next; $Alias{$find} = Encode::find_encoding($name); DEBUG and warn "$find => $name"; } } } if (DEBUG) { my $name; if ( my $e = $Alias{$find} ) { $name = $e->name; } else { $name = ""; } warn "find_alias($class, $find)->name = $name"; } return $Alias{$find}; } sub define_alias { while (@_) { my ( $alias, $name ) = splice( @_, 0, 2 ); unshift( @Alias, $alias => $name ); # newer one has precedence if ( ref($alias) ) { # clear %Alias cache to allow overrides my @a = keys %Alias; for my $k (@a) { if ( ref($alias) eq 'Regexp' && $k =~ $alias ) { DEBUG and warn "delete \$Alias\{$k\}"; delete $Alias{$k}; } elsif ( ref($alias) eq 'CODE' ) { DEBUG and warn "delete \$Alias\{$k\}"; delete $Alias{ $alias->($name) }; } } } else { DEBUG and warn "delete \$Alias\{$alias\}"; delete $Alias{$alias}; } } } # Allow latin-1 style names as well # 0 1 2 3 4 5 6 7 8 9 10 our @Latin2iso = ( 0, 1, 2, 3, 4, 9, 10, 13, 14, 15, 16 ); # Allow winlatin1 style names as well our %Winlatin2cp = ( 'latin1' => 1252, 'latin2' => 1250, 'cyrillic' => 1251, 'greek' => 1253, 'turkish' => 1254, 'hebrew' => 1255, 'arabic' => 1256, 'baltic' => 1257, 'vietnamese' => 1258, ); init_aliases(); sub undef_aliases { @Alias = (); %Alias = (); } sub init_aliases { require Encode; undef_aliases(); # Try all-lower-case version should all else fails define_alias( qr/^(.*)$/ => '"\L$1"' ); # UTF/UCS stuff define_alias( qr/^(unicode-1-1-)?UTF-?7$/i => '"UTF-7"' ); define_alias( qr/^UCS-?2-?LE$/i => '"UCS-2LE"' ); define_alias( qr/^UCS-?2-?(BE)?$/i => '"UCS-2BE"', qr/^UCS-?4-?(BE|LE)?$/i => 'uc("UTF-32$1")', qr/^iso-10646-1$/i => '"UCS-2BE"' ); define_alias( qr/^UTF-?(16|32)-?BE$/i => '"UTF-$1BE"', qr/^UTF-?(16|32)-?LE$/i => '"UTF-$1LE"', qr/^UTF-?(16|32)$/i => '"UTF-$1"', ); # ASCII define_alias( qr/^(?:US-?)ascii$/i => '"ascii"' ); define_alias( 'C' => 'ascii' ); define_alias( qr/\b(?:ISO[-_]?)?646(?:[-_]?US)?$/i => '"ascii"' ); # Allow variants of iso-8859-1 etc. define_alias( qr/\biso[-_]?(\d+)[-_](\d+)$/i => '"iso-$1-$2"' ); # At least HP-UX has these. define_alias( qr/\biso8859(\d+)$/i => '"iso-8859-$1"' ); # More HP stuff. define_alias( qr/\b(?:hp-)?(arabic|greek|hebrew|kana|roman|thai|turkish)8$/i => '"${1}8"' ); # The Official name of ASCII. define_alias( qr/\bANSI[-_]?X3\.4[-_]?1968$/i => '"ascii"' ); # This is a font issue, not an encoding issue. # (The currency symbol of the Latin 1 upper half # has been redefined as the euro symbol.) define_alias( qr/^(.+)\@euro$/i => '"$1"' ); define_alias( qr/\b(?:iso[-_]?)?latin[-_]?(\d+)$/i => 'defined $Encode::Alias::Latin2iso[$1] ? "iso-8859-$Encode::Alias::Latin2iso[$1]" : undef' ); define_alias( qr/\bwin(latin[12]|cyrillic|baltic|greek|turkish| hebrew|arabic|baltic|vietnamese)$/ix => '"cp" . $Encode::Alias::Winlatin2cp{lc($1)}' ); # Common names for non-latin preferred MIME names define_alias( 'ascii' => 'US-ascii', 'cyrillic' => 'iso-8859-5', 'arabic' => 'iso-8859-6', 'greek' => 'iso-8859-7', 'hebrew' => 'iso-8859-8', 'thai' => 'iso-8859-11', ); # RT #20781 define_alias(qr/\btis-?620\b/i => '"iso-8859-11"'); # At least AIX has IBM-NNN (surprisingly...) instead of cpNNN. # And Microsoft has their own naming (again, surprisingly). # And windows-* is registered in IANA! define_alias( qr/\b(?:cp|ibm|ms|windows)[-_ ]?(\d{2,4})$/i => '"cp$1"' ); # Sometimes seen with a leading zero. # define_alias( qr/\bcp037\b/i => '"cp37"'); # Mac Mappings # predefined in *.ucm; unneeded # define_alias( qr/\bmacIcelandic$/i => '"macIceland"'); define_alias( qr/^mac_(.*)$/i => '"mac$1"' ); # http://rt.cpan.org/Ticket/Display.html?id=36326 define_alias( qr/^macintosh$/i => '"MacRoman"' ); # Ououououou. gone. They are differente! # define_alias( qr/\bmacRomanian$/i => '"macRumanian"'); # Standardize on the dashed versions. define_alias( qr/\bkoi8[\s\-_]*([ru])$/i => '"koi8-$1"' ); unless ($Encode::ON_EBCDIC) { # for Encode::CN define_alias( qr/\beuc.*cn$/i => '"euc-cn"' ); define_alias( qr/\bcn.*euc$/i => '"euc-cn"' ); # define_alias( qr/\bGB[- ]?(\d+)$/i => '"euc-cn"' ) # CP936 doesn't have vendor-addon for GBK, so they're identical. define_alias( qr/^gbk$/i => '"cp936"' ); # This fixes gb2312 vs. euc-cn confusion, practically define_alias( qr/\bGB[-_ ]?2312(?!-?raw)/i => '"euc-cn"' ); # for Encode::JP define_alias( qr/\bjis$/i => '"7bit-jis"' ); define_alias( qr/\beuc.*jp$/i => '"euc-jp"' ); define_alias( qr/\bjp.*euc$/i => '"euc-jp"' ); define_alias( qr/\bujis$/i => '"euc-jp"' ); define_alias( qr/\bshift.*jis$/i => '"shiftjis"' ); define_alias( qr/\bsjis$/i => '"shiftjis"' ); define_alias( qr/\bwindows-31j$/i => '"cp932"' ); # for Encode::KR define_alias( qr/\beuc.*kr$/i => '"euc-kr"' ); define_alias( qr/\bkr.*euc$/i => '"euc-kr"' ); # This fixes ksc5601 vs. euc-kr confusion, practically define_alias( qr/(?:x-)?uhc$/i => '"cp949"' ); define_alias( qr/(?:x-)?windows-949$/i => '"cp949"' ); define_alias( qr/\bks_c_5601-1987$/i => '"cp949"' ); # for Encode::TW define_alias( qr/\bbig-?5$/i => '"big5-eten"' ); define_alias( qr/\bbig5-?et(?:en)?$/i => '"big5-eten"' ); define_alias( qr/\btca[-_]?big5$/i => '"big5-eten"' ); define_alias( qr/\bbig5-?hk(?:scs)?$/i => '"big5-hkscs"' ); define_alias( qr/\bhk(?:scs)?[-_]?big5$/i => '"big5-hkscs"' ); } # utf8 is blessed :) define_alias( qr/\bUTF-8$/i => '"utf-8-strict"' ); # At last, Map white space and _ to '-' define_alias( qr/^(\S+)[\s_]+(.*)$/i => '"$1-$2"' ); } 1; __END__ # TODO: HP-UX '8' encodings arabic8 greek8 hebrew8 kana8 thai8 turkish8 # TODO: HP-UX '15' encodings japanese15 korean15 roi15 # TODO: Cyrillic encoding ISO-IR-111 (useful?) # TODO: Armenian encoding ARMSCII-8 # TODO: Hebrew encoding ISO-8859-8-1 # TODO: Thai encoding TCVN # TODO: Vietnamese encodings VPS # TODO: Mac Asian+African encodings: Arabic Armenian Bengali Burmese # ChineseSimp ChineseTrad Devanagari Ethiopic ExtArabic # Farsi Georgian Gujarati Gurmukhi Hebrew Japanese # Kannada Khmer Korean Laotian Malayalam Mongolian # Oriya Sinhalese Symbol Tamil Telugu Tibetan Vietnamese