apply.md

apply

Description

Calls $fn with $args and returns its results.

This function tries to solve the problem of calling a function stored in a class attribute, because if you try $this->callable($arg1, $arg2) PHP expects $this->callable to be a function and not a property. And to avoid use the magic method invoke that will properly work $this->callable->__invoke($arg1, $arg2) we use go with apply($this->callable, [$arg1, $arg2]).

Be aware that using this function most IDEs will lose the path, so they will not detect that your are passing the wrong number of parameters or will not do as you expect a change of signature. To have a good test suite would be a requirement for a widely use of this function in your code.

Parameters

fn

Function to be executed.

args

Arguments to be passed to the called function.

Examples

Call a closure stored in an attribute of a class:

<?php

use function Lambdish\Phunctional\apply;

class Operation
{
    private $operator;

    public function __construct(callable $operatorToBeApplied)
    {
        $this->operator = $operatorToBeApplied;
    }

    public function calc($first, $second)
    {
        return apply($this->operator, [$first, $second]);
    }
}

$sum = new Operation(static function ($first, $second) { return $first + $second;});

return $sum->calc(1, 2);

// => 3