man Tie::RegexpHash (3): Use regular expressions as hash keys

SYNOPSIS

use Tie::RegexpHash;
my %hash;
tie %hash, 'Tie::RegexpHash';
$hash{ qr/^5(\s+|-)?gal(\.|lons?)?/i } = '5-GAL';
$hash{'5 gal'}; # returns "5-GAL"
$hash{'5GAL'}; # returns "5-GAL"
$hash{'5 gallon'}; # also returns "5-GAL"
my $rehash = Tie::RegexpHash->new();
$rehash->add( qr/\d+(\.\d+)?/, "contains a number" );
$rehash->add( qr/s$/, "ends with an \`s\'" );
$rehash->match( "foo 123" ); # returns "contains a number"
$rehash->match( "examples" ); # returns "ends with an `s'"

DESCRIPTION

This module allows one to use regular expressions for hash keys, so that values can be associated with anything that matches the key.

Hashes can be operated on using the standard tied hash interface in Perl, or using an object-oriented interface described below.

Methods

new

  my $obj = Tie::RegexpHash->new()

Creates a new ``RegexpHash'' (Regular Expression Hash) object.

add

  $obj->add( $key, $value );

Adds a new key/value pair to the hash. $key can be a Regexp or a string (which is compiled into a Regexp).

If $key is already defined, the value will be changed. If $key matches an existing key (but is not the same), a warning will be shown if warnings are enabled.

match

  $value = $obj->match( $quasikey );

Returns the value associated with $quasikey. ($quasikey can be a string which matches an existing Regexp or an actual Regexp.) Returns 'undef' if there is no match.

Regexps are matched in the order they are defined.

match_exists

  if ($obj->match_exists( $quasikey )) ...

Returns a true value if there exists a matching key.

remove

  $value = $obj->remove( $quasikey );

Deletes the key associated with $quasikey. If $quasikey matches an existing key (but is not the same), a warning will be shown.

Returns the value associated with the key.

clear

  $obj->clear();

Removes all key/value pairs.

AUTHOR

Robert Rothenberg <rrwo at cpan.org>

Acknowledgments

Russell Harrison <rch at cpan.org> for patches adding support for serialization.

Simon Hanmer <sch at scubaplus.co.uk> & Bart Vetters <robartes at nirya.eb> for pointing out a bug in the logic of the _find() routine in v0.10

LICENSE