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Map::Agnostic - be a map without knowing how


use Map::Agnostic;
class MyMap does Map::Agnostic {
    method INIT-KEY($key,$value) { ... }
    method AT-KEY($key)          { ... }
    method EXISTS-KEY($key)      { ... }
    method keys()                { ... }

my %m is MyMap = a => 42, b => 666;

my %m is Map::Agnostic = ...;


This module makes a Map::Agnostic role available for those classes that wish to implement the Associative role as an immutable Map. It provides all of the Map functionality while only needing to implement 4 methods:

Required Methods

method INIT-KEY

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

Bind the given value to the given key in the map, and return the value. This will only be called during initialization of the Map. The functionality is the same as the BIND-KEY method, but it will only be called at initialization time, whereas BIND-KEY can be called at any time and will fail.

method AT-KEY

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

Return the value at the given key in the map.


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

Return Bool indicating whether the key exists in the map.

method keys

method keys() { ... }

Return the keys that currently exist in the map, 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 Map object.

In alphabetical order: elems, end, gist, Hash, iterator, kv, list, List, new, pairs, perl, Slip, STORE, Str, values


Elizabeth Mattijsen liz@raku.rocks

Source can be located at: https://github.com/lizmat/Map-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 2018, 2019, 2021, 2023, 2024 Elizabeth Mattijsen

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