How to dynamically define a nested PHP function using parent function parameters

Question

I tried looking everywhere for this, or perhaps it just cannot be done?

So say I want to have a function that is used to create other functions which have a new function name based on a passed in argument, is this even possible?

I keep getting function undefined. Beyond the currying ability, can you name the nested function with a parameter and return the nested function to be called later (by the name you gave it in the parameter)?

function maker_of_functions($secFuncName, $foo) { 
    $secFuncName = function($bar) { 
        $fooBar = $foo + $bar;
    }
    return $secFuncName();
}

The later in the code call:

maker_of_functions('adder', 3);
echo adder(5);

Possible duplicate of Is it possible to curry method calls in PHP? — u_mulder
– u_mulder, Commented Aug 2, 2016 at 20:31
The question is mainly bout can you define (and name) a nested function with the parent function parameter. — Secular12
– Secular12, Commented Aug 2, 2016 at 20:53
If I am not wrong, that child function will only exists as long as the parent function is alive and therefore, can only be used from inside the parent function itself? — coderodour
– coderodour, Commented Aug 2, 2016 at 21:20

Community · Accepted Answer · 2017-05-23 12:32:53Z

2

Using parent function parameters

To create a new function which uses the parent function params, you can use a closure:

function maker_of_functions($foo) { 
    // notice the "use" keyword below
    return function($bar) use ($foo) { 
        return $foo + $bar;
    };
}

and then use it:

$adder = maker_of_functions(3);
echo $adder(5);

Naming the function

A closure is an anonymous function. It does not have a name. It exist as (I think) a reference to a function only, which is contained in a variable. If you want a dynamically named variable, you can:

$name = "myNewNamedFunction";
$$name = maker_of_functions(3);

echo $myNewNamedFunction(6);

Additional information

edited May 23, 2017 at 12:32

CommunityBot

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answered Aug 2, 2016 at 21:01

Emile Bergeron

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1 Comment

Secular12 Over a year ago

Thank you very much, this will do just fine! Works exactly as I would need.

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Using parent function parameters

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