NAME

Hash::Agnostic - be a hash without knowing how

SYNOPSIS

use Hash::Agnostic;
class MyHash does Hash::Agnostic {
    method AT-KEY($key)          { ... }
    method keys()                { ... }
}

my %a is MyHash = a => 42, b => 666;

DESCRIPTION

This module makes an Hash::Agnostic role available for those classes that wish to implement the Associative role as a Hash. It provides all of the Hash functionality while only needing to implement 2 methods:

Required Methods

method AT-KEY

method AT-KEY($key) { ... }  # simple case

method AT-KEY($key) { Proxy.new( FETCH => { ... }, STORE => { ... } }

Return the value at the given key in the hash. Must return a Proxy that will assign to that key if you wish to allow for auto-vivification of elements in your hash.

method keys

method keys() { ... }

Return the keys that currently exist in the hash, in any order that is most convenient.

Optional Methods (provided by role)

You may implement these methods out of performance reasons yourself, but you don't have to as an implementation is provided by this role. They follow the same semantics as the methods on the Hash object.

In alphabetical order: append, ASSIGN-KEY, elems, end, gist, grab, Hash, iterator, kv, list, List, new, pairs, perl, push, Slip, STORE, Str, values

Optional Internal Methods (provided by role)

These methods may be implemented by the consumer for performance reasons or to provide a given capability.

method BIND-KEY

method BIND-KEY($key, $value) { ... }

Bind the given value to the given key in the hash, and return the value. Throws an error if not implemented.

method DELETE-KEY

method DELETE-KEY($key) { ... }

Remove the the given key from the hash and return its value if it existed (otherwise return Nil). Throws an error if not implemented.

method EXISTS-KEY

method EXISTS-KEY($key) { ... }

Return Bool indicating whether the key exists in the hash. Will call AT-KEY and return True if the returned value is defined.

method CLEAR

method CLEAR(--> Nil) { ... }

Reset the array to have no elements at all. By default implemented by repeatedly calling DELETE-KEY, which will by all means, be very slow. So it is a good idea to implement this method yourself.

AUTHOR

Elizabeth Mattijsen liz@raku.rocks

Source can be located at: https://github.com/lizmat/Hash-Agnostic . Comments and Pull Requests are welcome.

If you like this module, or what I’m doing more generally, committing to a small sponsorship would mean a great deal to me!

COPYRIGHT AND LICENSE

Copyright 2018, 2020, 2023 Elizabeth Mattijsen

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

License

lizmat/Hash-Agnostic

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