NAME

Convert::DUDE - Conversion between Unicode and DUDE

SYNOPSIS

  use Convert::DUDE ':all';

  # handles 'dq--' prefix
  $domain  = to_dude($utf8);
  $utf8    = from_dude($domain);

  # don't care about 'dq--' prefix
  # not exported by default           
  $dudestr = dude_encode($utf8);
  $utf8    = dude_decode($dudestr);

DESCRIPTION

This module provides functions to convert between DUDE (Differential Unicode Domain Encoding) and Unicode encodings.

Quoted from http://www.i-d-n.net/draft/draft-ietf-idn-dude-02.txt

  DUDE is a reversible transformation from a sequence of nonnegative
  integer values to a sequence of letters, digits, and hyphens (LDH
  characters).  DUDE provides a simple and efficient ASCII-Compatible
  Encoding (ACE) of Unicode strings for use with Internationalized
  Domain Names.

FUNCTIONS

Following two functions are exported to your package when you use Convert::DUDE.

to_dude

  $domain = to_dude($utf8);

takes UTF8-encoded string, encodes it in DUDE and adds 'dq--' prefix in front.

from_dude

  $utf8 = from_dude($domain);

takes 'dq--' prefixed DUDE encoded string and decodes it to original UTF8 strings.

Following two functions can be exported to your package when you import them explicitly.

dude_encode

  $dude = dude_encode($utf8);

takes UTF8-encoded string, encodes it in DUDE. Note that it doesn't care about 'dq--' prefix.

dude_decode

  $utf8 = dude_decode($dude);

takes DUDE encoded string and decodes it to original UTF8 strings. Note that it doesn't care about 'dq--' prefix.

Those functions above may throw exeptions in case of error. You may have to catch 'em with eval block.

CLASS METHODS

prefix

  $prefix = Convert::DUDE->prefix;
  Convert::DUDE->prefix('xx--');

gets/sets DUDE prefix. 'dq--' for default.

EXAMPLES

Here's a sample code which does RACE-DUDE conversion.

  use Convert::RACE;
  use Convert::DUDE;
  use Unicode::String qw(utf16);
               
  my $race = "bq--aewrcsy";

  eval {
      my $utf16 = from_race($race);
      my $dude = to_dude(utf16($utf16)->utf8);
      print "RACE: $race => DUDE: $dude\n";
  };

  if ($@) {
      warn "Conversion failed: $@";
  }
  

CAVEATS

• There's no constraints on the input. See internet draft for nameprep about IDN input validation.

TODO

• Consider mixed-case annotation. See internet draft for DUDE for details.

AUTHOR

Tatsuhiko Miyagawa <miyagawa@bulknews.net>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

This module comes without warranty of any kind.

SEE ALSO

Convert::RACE, http://www.i-d-n.net/, http://www.i-d-n.net/draft/draft-ietf-idn-dude-02.txt, Unicode::String, Jcode