Closures

A closure or callback function is a new feature as of PHP 5.3. Closures makes it easy to create recursive code and small functions that does not need to be in the global scope.

<?php $closure = funciton($what){
	echo "Hello {$what}!";
}

// Runs the function like any other function but with dollar ($) sign infront to call to the variable.
$closure('World');

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The use statement

Sometimes you would want to access global variables outside of the function itself, its accomplished using the use statement.

<?php $what = 'World';

$closure = funciton() use ($what){
	echo "Hello {$what}!";
}

$closure();
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Passing callback functions to other functions

Sometimes you want to pass the function to another function or class method. This is the correct way:

<?php function test($closure){
	// Check if the variable is a closure.
	if (is_callable($closure)){
		$number = $closure();
	}
}

$closure = function(){
	return 1;
};

test($closure);

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