NAME
    Tie::RangeHash - Allows hashes to associate values with a range of keys

REQUIREMENTS
    Perl 5.6.1 is required.

    Algorithm::SkipList is required.  Otherwise it uses standard modules.

  Installation
    Installation can be done using the traditional Makefile.PL or the
    newer Build.PL methods.

    Using Makefile.PL:

      perl Makefile.PL
      make
      make test
      make install

    (On Windows platforms you should use nmake instead.)

    Using Build.PL (if you have Module::Build installed):

      perl Build.PL
      perl Build
      perl Build test
      perl Build install    

HISTORY
    Changes since Tie::RangeHash 1.00_2

    1.01   Fri Dec 17 2004
	- uses base
	- added SIGNATURE
	* updated to use Algorithm::SkipList
	- uses Exporter
	* removed validate_key() methods from node types (for now)
	- commented out Carp::Assert
	- added reset method
	- version conforms to proper Perl style
	- added size method
	- modified tests
	- added stub for autosplit in Build.PL

    A detailed revision history is in the Changes file included with
    this distribution.    

SYNOPSIS
      use Tie::RangeHash;

      tie %hash, 'Tie::RangeHash';

      $hash{'A,C'} = 1;
      $hash{'D,F'} = 2;
      $hash{'G,K'} = 3;

      $hash{'E'};           # returns '2'
      $hash{'BB'};          # returns '1'

      $hash{'KL'};          # returns nothing ('undef')

    There is also an object-oriented interface:

      $hash = new Tie::RangeHash;

      $hash->add('A,C', 1);
      $hash->add('G,I', 2);

      $hash->fetch('H');    # returns '2'

DESCRIPTION
    This module allows hashes to associate a value with a *range* of keys
    rather than a single key.

    A more detailed description can be found in the module's POD docu-
    mentation.

KNOWN ISSUES
    The is a new version of the module and has behaves differently compared
    to older versions. This is due to using the List::SkipList module for
    maintaining the underlying data rather than re-implementing it.  While
    this improves the maintainability with the code, it increases incom-
    patability with previous versions.

    Some of the changes include:

    Overlapping keys cause fatal errors instead of warnings
        Because the key comparison is now performed in the skip list node,
        there is no obvious way for it to give a warning and return a
        meaningful result. So instead the code dies. If you code relies on
        the possibility of using overlapping keys, then it may be more
        appropriate to have it test the code:

          eval {
            $hash{'111,999'} = $value;
          };

        This error can also occur by merely testing a hash, so it is
        important to run some checks if you are testing hash ranges:

          eval {
            if ($hash{'111,999'} == $value) { ... }
          }

    Keys can be redefined
        Nodes can now be redefined. For example:

          $hash{'1,3'} = $value;
          ...
          $hash{'1,3'} = $new_value;
          ...
          $hash{'2'}   = $new_value;

        Note that a range is no longer required.

    Non-range keys can be added.
        When inserting a key, "$hash{'x'}" will be treated like
        "$hash{'x,x'}".

    Open-ended ranges are allowed.
        Open ended ranges are now supported. So the following can be added:

          $hash{',10'} = $upper_bound;
          $hash{'11,'} = $lower_bound;

    array references can no longer be keys.
        The following is *not* supported anymore:

          $hash{ \@array ) = $value;

    warnings no longer registered.
        Warning registration is no longer used. This may change in the
        future.

    Custom separators and comparisons are not supported.
        Only commas can be used as separators.

        To customize separators and comparisons, you will have to specify a
        custom List::SkipList::Node method.

    See the the Changes manpage file for a more complete list of
    incompatabilities.

    If your code does not rely on these quirks, then you should be able to
    substitute with no problems.

SEE ALSO
    A module with similar functionality for numerical values is
    Array::IntSpan.

    Algorithm::SkipList for more information on skip lists.

AUTHOR
    Robert Rothenberg <rrwo at cpan.org>

LICENSE
    Copyright (C) 2000-2004 Robert Rothenberg. All rights reserved. This
    program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

