PHP: Create global function out of anonymous function

Question

I want to create global function with dynamic name, but I dont want to write code of function as string, as it's required in PHP docs about create_function function.

Dream scenario would be like:

$functionName = "new_super_function";
$functionBody = function($a,$b) { return $a + $b; };

if ( !function_exists($functionName) ) create_function($functionName, $functionBody);

//from here my function with dynamic name is ready
//I could now call it like call_user_func($functionName, 5, 7) => 12
//or just use it later like new_super_function(5,7) => 12

I was looking for such sort of possibility but I couldnt find anything. Any ideas?

Rizier123 · Accepted Answer · 2015-05-05 10:23:02Z

3

Just assign the function body to the function name like this:

$functionName = "new_super_function";
$functionBody = function($a,$b) { return $a + $b; };

if (!function_exists($functionName))
    $functionName = $functionBody;

echo call_user_func($functionName, 5, 7);  //Same as: echo $functionName(5, 7);

output:

EDIT:

If you want to declare an anonymous function which you can also call in other function, this won't be possible, since it is assigned to a variable and the variable is in a scope, so you either have to pass the variable with the anonymous function as argument or use the global keyword.

edited May 5, 2015 at 10:23

answered May 5, 2015 at 10:09

Rizier123

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6 Comments

pie6k Over a year ago

Will it be global function with given name?

Rizier123 Over a year ago

@AdamPietrasiak Since it is an anonymous function assigned to a variable no

pie6k Over a year ago

Well, my point is to create global function with given name, I've edited question to point that

Rizier123 Over a year ago

@AdamPietrasiak Why do you even want to do this? I think if you would have to create a function dynamically you have to rethink your code logic

Rizier123 Over a year ago

@AdamPietrasiak Also this is not possible, since an anonymous function is assigned to a variable and the variable is in a scope, so you won't be able to call it in another function if you don't pass it as argument or use global keyword

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Furgas · Accepted Answer · 2015-05-05 11:15:40Z

I thought it would be fun to try to answer it. You would have to create your own create_function method.

function my_create_function($name, $callable) {
    $GLOBALS['my_functions'][$name] = $callable;

    $call_wrapper = sprintf('function %s() {
        $arguments = func_get_args();
        return call_user_func_array($GLOBALS["my_functions"][%s], $arguments);
    }', $name, $name);

    eval($call_wrapper);
}

Test:

class Test {
    static public function prepare() {
        $add_function = function($a, $b) { return $a + $b; };

        var_dump($add_function(1, 2));

        my_create_function('my_add', $add_function);
    }

    static public function testit() {
        var_dump(call_user_func('my_add', 1, 2));

        var_dump(call_user_func_array('my_add', array(1, 2)));

        var_dump(my_add(1, 2));
    }
}

Test::prepare();
Test::testit();

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