NAME

Unicode::Stringprep - Preparation of Internationalized Strings (RFC 3454)

SYNOPSIS

use Unicode::Stringprep;
use Unicode::Stringprep::Mapping;
use Unicode::Stringprep::Prohibited;

my $prepper = Unicode::Stringprep->new(
  3.2,
  [ { 32 => '<SPACE>'},  ],
  'KC',
  [ @Unicode::Stringprep::Prohibited::C12, @Unicode::Stringprep::Prohibited::C22,
    @Unicode::Stringprep::Prohibited::C3, @Unicode::Stringprep::Prohibited::C4,
    @Unicode::Stringprep::Prohibited::C5, @Unicode::Stringprep::Prohibited::C6,
    @Unicode::Stringprep::Prohibited::C7, @Unicode::Stringprep::Prohibited::C8,
    @Unicode::Stringprep::Prohibited::C9 ],
  1 );
$output = $prepper($input)

DESCRIPTION

This module implements the stringprep framework for preparing Unicode text strings in order to increase the likelihood that string input and string comparison work in ways that make sense for typical users throughout the world. The stringprep protocol is useful for protocol identifier values, company and personal names, internationalized domain names, and other text strings.

The stringprep framework does not specify how protocols should prepare text strings. Protocols must create profiles of stringprep in order to fully specify the processing options.

This module provides a single function, new, that creates a perl function implementing a stringprep profile.

FUNCTIONS

new($unicode_version, $mapping_tables, $unicode_normalization, $prohibited_tables, $bidi_check)

Creates a callable object that implements a stringprep profile.

$unicode_version is the Unicode version specified by the stringprep profile. Currently, this must be 3.2.

$mapping_tables provides the mapping tables used for stringprep. It may be a reference to a hash or an array. A hash must map Unicode codepoints (as integers, e. g. 0x0020 for U+0020) to replacement strings (as perl strings). An array may contain pairs of Unicode codepoints and replacement strings as well as references to nested hashes and arrays. Unicode::Stringprep::Mapping provides the tables from RFC 3454, Appendix B. For further information on the mapping step, see RFC 3454, section 3.

$unicode_normalization is the Unicode normalization to be used. Currently, '' (no normalization) and 'KC' (compatibility composed) are specified for stringprep. For further information on the normalization step, see RFC 3454, section 4.

$prohibited_tables provides the list of prohibited output characters for stringprep. It may be a reference to an array. The array contains pairs of codepoints, which define the start and end of a Unicode character range (as integers). The end character may be undef, specifying a single-character range. The array may also contain references to nested arrays. Unicode::Stringprep::Prohibited provides the tables from RFC 3454, Appendix C. For further information on the prohibition checking step, see RFC 3454, section 5.

$bidi_check must be set to true if additional checks for bidirectional characters are required. For further information on the bidi checking step, see RFC 3454, section 6.

The function returned can be called with a single parameter, the string to be prepared, and returns the prepared string. It will die if the input string is invalid (so use eval if necessary).

For performance reasons, it is strongly recommended to call the new function as few times as possible, i. e. once per stringprep profile. It might also be better not to use this module directly but to use (or write) a module implementing a profile, such as Net::IDN::Nameprep.

IMPLEMENTING PROFILES

You can easily implement a stringprep profile without subclassing:

package ACME::ExamplePrep;

use Unicode::Stringprep;

use Unicode::Stringprep::Mapping;
use Unicode::Stringprep::Prohibited;

*exampleprep = Unicode::Stringprep->new(
  3.2,
  [ 
    @Unicode::Stringprep::Mapping::B1, 
  ],
  '',
  [
    @Unicode::Stringprep::Prohibited::C12,
    @Unicode::Stringprep::Prohibited::C22,
  ],
  1,
);

This binds ACME::ExamplePrep::exampleprep to the function created by Unicode::Stringprep->new.

Usually, it is not necessary to subclass this module. Sublassing this module is not recommended.

DATA TABLES

The following modules contain the data tables from RFC 3454:

• Unicode::Stringprep::Unassigned

  @Unicode::Stringprep::Unassigned::A1	# Appendix A.1

• Unicode::Stringprep::Mapping

  @Unicode::Stringprep::Mapping::B1	# Appendix B.1
  @Unicode::Stringprep::Mapping::B2	# Appendix B.2
  @Unicode::Stringprep::Mapping::B2	# Appendix B.3

• Unicode::Stringprep::Prohibited

  @Unicode::Stringprep::Prohibited::C11	# Appendix C.1.1
  @Unicode::Stringprep::Prohibited::C12	# Appendix C.1.2
  @Unicode::Stringprep::Prohibited::C21	# Appendix C.2.1
  @Unicode::Stringprep::Prohibited::C22	# Appendix C.2.2
  @Unicode::Stringprep::Prohibited::C3	# Appendix C.3
  @Unicode::Stringprep::Prohibited::C4	# Appendix C.4
  @Unicode::Stringprep::Prohibited::C5	# Appendix C.5
  @Unicode::Stringprep::Prohibited::C6	# Appendix C.6
  @Unicode::Stringprep::Prohibited::C7	# Appendix C.7
  @Unicode::Stringprep::Prohibited::C8	# Appendix C.8
  @Unicode::Stringprep::Prohibited::C9	# Appendix C.9

• Unicode::Stringprep::BiDi

  @Unicode::Stringprep::BiDi::D1	# Appendix D.1
  @Unicode::Stringprep::BiDi::D2	# Appendix D.2

AUTHOR

Claus Färber <CFAERBER@cpan.org>

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

SEE ALSO

Unicode::Normalize, RFC 3454