What did I see?

I saw in a PHP class using this method __invoke

1
2
3
4

public function __invoke(int $errorNumber, string $errorString, string $errorFile, int $errorLine): bool
{
    ...
}

Why using this method?

This magic method is called when user tries to invoke object as a function. Possible use cases may include some approaches like functional programming or some callbacks.

How do people use it?

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

class Invokable
{
    /**
     * This method will be called if object will be executed like a function:
     *
     * $invokable();
     *
     * Args will be passed as in regular method call.
     */
    public function __invoke($arg, $arg, ...)
    {
        print_r(func_get_args());
    }
}

// Example:
$invokable = new Invokable();
$invokable([1, 2, 3]);

// optputs:
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
)