Partial function application with PHP

example.php

<?php
function foo($a, $b) {
    echo "a: {$a} b: {$b}\n";
}

$foo_caller = new PartialCallable('foo', array('A'));
$foo_caller('B');

$foo_caller = partial_function('foo', 'A');
$foo_caller('B');

partial_callable.php

<?php
class PartialCallable {
    function __construct($callable, $args) {
        $this->callable = $callable;
        $this->args = $args;
    }
    
    function __invoke() {
        call_user_func_array($this->callable, array_merge($this->args, func_get_args()));
    }
}

partial_function.php

<?php
function partial_function() {
    $applied_args = func_get_args();
    return function() use($applied_args) {
        return call_user_func_array('call_user_func', array_merge($applied_args, func_get_args()));
    };
}