partial.php

<?php

/**
 * Original Source: http://www.gerbenjacobs.nl/push-new-value-into-array-with-php/
 */
function array_push_insert($array, $index, $value) {
    if (array_key_exists($index, $array)) {
        $firstArray = array_slice($array, 0, $index);
        $lastArray = array_slice($array, $index);
        array_push($firstArray, $value);
        $array = array_merge($firstArray, $lastArray);
    } else {
        $array[key] = $value;
    }
    return $array;
}

function partial($f, $p, $v) {
    $_f = new ReflectionFunction($f);
    $params = array();
    foreach ($_f->getParameters() as $param) {
        $params[] = $param->name;
    }
    $i = array_search($p, $params);
    return function() use ($_f, $i, $v) {
        $args = func_get_args();
        $args = array_push_insert($args, $i, $v);
        return $_f->invokeArgs($args);
    };
}

function t($a, $b, $c) {
    return $a + (2*$b) + (3*$c);
}

$t_p = partial(t, 'a', 7);
$res = $t_p(1, 3);
echo $res . "\n"; // 18

$t_p = partial(t, 'b', 7);
$res = $t_p(1, 3);
echo $res . "\n"; // 24

$t_p = partial(t, 'c', 7);
$res = $t_p(1, 3);
echo $res . "\n"; // 28