NAME
    Text::Scan - Fast search for very large numbers of keys in a body of
    text.

SYNOPSIS
            use Text::Scan;

            $dict = new Text::Scan;

            %terms = ( dog  => 'canine',
                       bear => 'ursine',
                       pig  => 'porcine' );

            # load the dictionary with keys and values
            # (values can be any scalar, keys must be strings)
            while( ($key, $val) = each %terms ){
                    $dict->insert( $key, $val );
            }

            # Scan a document for matches
            %found = $dict->scan( $document );

            # Or, if you need to count number of occurrences of any given 
            # key, use an array. This will give you a countable flat list
            # of key => value pairs.
            @found = $dict->scan( $document );

            # Check for membership ($val is true)
            $val = $dict->has('pig');

            # Retrieve all keys
            @keys = $dict->keys();

DESCRIPTION
    This module provides facilities for fast searching on arbitrarily long
    texts with arbitrarily many search keys. The basic object behaves
    somewhat like a perl hash, except that you can retrieve based on a
    superstring of any keys stored. Simply scan a string as shown above and
    you will get back a perl hash (or list) of all keys found in the string
    (along with associated values). Longest/first order is observed (as in
    perl regular expressions).

    IMPORTANT: As of this version, a single space is used as a delimiter for
    purposes of recognizing key boundaries. That's right, there is a bias in
    favor of processing natural language! In other words, if 'my dog' is a
    key and 'my dogs bite' is the text, 'my dog' will not be recognized. I
    plan to make this more configurable in the future, to have a different
    delimiter or none at all. For now, recognize that the key 'drunk' will
    not be found in the text 'gedrunk' or 'drunken' (or 'drunk.' for that
    matter). Properly tokenizing your corpus is essential. I know there is
    probably a better solution to the problem of substrings, and if anyone
    has suggestions, by all means contact me.

CREDITS
    Except for the actual scanning part, plus the node-rotation for
    self-adjusting optimization, this code is heavily borrowed from both
    Bentley & Sedgwick and Leon Brocard's additions to it for
    `Tree::Ternary_XS'.

    Many test scripts come directly from Rogaski's `Tree::Ternary' module.

    The C code interface was created using Ingerson's `Inline'.

SEE ALSO
    `Bentley & Sedgwick "Fast Algorithms for Sorting and Searching Strings",
    Proceedings ACM-SIAM (1997)'

    `Bentley & Sedgewick "Ternary Search Trees", Dr Dobbs Journal (1998)'

    `Sleator & Tarjan "Self-Adjusting Binary Search Trees", Journal of the
    ACM (1985)'

    `Tree::Ternary'

    `Tree::Ternary_XS'

    `Inline'

COPYRIGHT
    Copyright 2001 Ira Woodhead, H5 Technologies. All rights reserved.

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

AUTHOR
    Ira Woodhead, bunghole@pobox.com