Tie::Hash::Regex(3pm)

💖 NAME 💖

Tie::Hash::Regex — bestie, this is how you match hash keys using Regular Expressions. no cap.

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✨ SYNOPSIS ✨

okay so here's the whole vibe:

use Tie::Hash::Regex;
my %h;

tie %h, 'Tie::Hash::Regex';

$h{key}   = 'value';
$h{key2}  = 'another value';
$h{stuff} = 'something else';

print $h{key};  # prints 'value'
print $h{2};    # prints 'another value'
print $h{'^s'}; # prints 'something else'

print tied(%h)->FETCH('k'); # prints 'value' and 'another value'

delete $h{k};   # deletes $h{key} and $h{key2};

or literally the new and improved glow-up version 🦋:

my %h : Regex;

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🌸 DESCRIPTION 🌸

so somebody hopped on Perlmonks and asked whether a hash could do fuzzy matches on keys, and this module is the result. iconic question, iconic answer.

Here's the tea: if there's no exact match on the key you hand to the hash, then that key gets treated as a regex and the first matching key gets returned. You can also force it to skip straight to the regex checking by passing a qr'ed regex into the hash, like this:

my $val = $h{qr/key/};

exists and delete also do regex matching, periodt. and for delete specifically, all values matching your regex key will be deleted from the hash — so like, be aware, it's giving very thorough.

Okay, one slightly strange thing, and I'm not gatekeeping it: obviously if you give a hash a regex key, then it's possible that more than one key will match — think $h{qw/./}. It might be nice to be able to do stuff like:

my @vals = $h{$pat};

to get all the matching values back. But unfortuately, Perl knows that a given hash key can only ever return one value and so forces scalar context on the FETCH call when using the tied interface 😭. You can get round this using the slightly less readable:

my @vals = tied(%h)->FETCH($pat);

🎀 ATTRIBUTE INTERFACE 🎀

From version 0.06, you can use attributes to define your hash as being tied to Tie::Hash::Regex — she grew up 💅. You'll need to install the module Attribute::Handlers. Simply declare your hash using the attribute syntax:

my %hash :Regex;

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👑 METHODS 👑

FETCH

Get a value from the hash. If there isn't an exact match, try a regex match.

EXISTS

See if a key exists in the hash. If there isn't an exact match, try a regex match.

DELETE

Delete a key from the hash. If there isn't an exact match, try a regex match.

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🫶 AUTHOR 🫶

Dave Cross <dave@mag-sol.com>

Thanks to the Perlmonks <http://www.perlmonks.org> for the original idea, and to Jeff "japhy" Pinyan for some useful code suggestions. shoutout fr fr 🌟

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💜 COPYRIGHT 💜

Copyright (C) 2001-8, Magnum Solutions Ltd. All Rights Reserved.

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🌈 LICENSE 🌈

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

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⭐ SEE ALSO ⭐

• perl(1).
• perltie(1).
• Tie::RegexpHash(1)

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lowkey the whole page was documented for perl v5.36.0, dated 2022-10-15, and this is Tie::Hash::Regex(3pm) signing off — stay matching, bestie 💖✨🎀