ganglio/Memoizer

<?php

namespace ganglio;

class Memoizer
{

    const NOT_CALLABLE = 1;

    private $f = null;
    private $results = null;

    public function __construct($f)
    {
        if (!is_callable($f)) {
            throw new \InvalidArgumentException("Argument needs to be callable", self::NOT_CALLABLE);
        }

        $this->f = new \ReflectionFunction($f);
    }

    public function __invoke()
    {
        $args = func_get_args();
        $args_hash = spl_object_hash((object)$args);

        if (!isset($this->results[$args_hash])) {
            $this->results[$args_hash] = $this->f->invokeArgs($args);
        }

        return $this->results[$args_hash];
    }
}