Curry Pairs

curry-pairs.php

<?php
/**
 * curry-pairs.php
 *
 * @link http://stackoverflow.com/questions/10144996/permutations-of-values-in-array
 */

/**
 * @param array $a
 * @param array $b
 */
$funky = function($a, $b)
{
    printf("(%s) and (%s)\n", implode(',', $a), implode(',', $b));
};

/**
 * paired function of $function
 *
 * @param callback $function
 * @return Closure
 */
$paired = function($function)
{
    return function(array $array) use ($function)
    {
        $stack[] = array(array(), $array);
        while (list($left, $right) = array_pop($stack)) {
            $min = end($left);
            foreach ($right as $value)
            {
                if ($value < $min) continue;
                $left2 = array_merge($left, array($value));
                $right2 = array_diff($right, $left2);
                if (!($left2 && $count = count($right2))) continue;
                $function($left2, $right2);
                --$count && $stack[] = array($left2, $right2);
            }
        }
    };
};

$funkyAll = $paired($funky);
$funkyAll(range(1, 5));