Is it possible to create a named function from a closure?

Question

In PHP, you can have named functions like this:

function foo()
{
   return "bar";
}

And you can have Closures like this:

$foo = function() {
    return "bar";
};

Closures are awesome and easy to create, but unfortunately a library I need to use really wants a named function. Is it possible to create a named function from closures dynamically? I.e. not defining all functions in code ahead of time, but more like a register_function($name, callable $closure).

I am aware of create_function, but that one takes a PHP string as function body and just evals it, which is not what I'm looking for.

Answer 1

You can create global array with callbacks. Add to this global array by register_func($name, $callback) and call function by call_func($name, $parameter1, $parameter2, ...).

Without using eval I think this is not possible to create named function from callback.

Answer 2

I managed to create one using evil eval, ReflectionClass and SuperClosure library.

Here's my code:

<?php

function register_function(string $name, Closure $closure)
{
    $serializedBody = (new SuperClosure\Serializer)->serialize($closure);

    $obj = unserialize($serializedBody);
    $reflection = new ReflectionClass($obj);
    $property = $reflection->getProperty('data');
    $property->setAccessible(true);
    $data = $property->getValue($obj);
    $body = preg_replace('/^function \(/', "function {$name} (", $data['code']);

    eval($body);
}

$closure = function($a = 1, $b = 2, $c = 3) {
    var_dump(compact('a', 'b', 'c'));
};

register_function('test', $closure);

var_dump(function_exists('test')); // true

test(13, 2, 3);
// array(3) {
//   ["a"]=>
//   int(13)
//   ["b"]=>
//   int(2)
//   ["c"]=>
//   int(3)
// }