So I'm programming along in a nice, up to date, object oriented fashion. I regularly make use of the various aspects of OOP that PHP implements but I am wondering when might I need to use closures. Any experts out there that can shed some light on when it would be useful to implement closures?
PHP will support closures natively in 5.3. A closure is good when you want a local function that's only used for some small, specific purpose. The RFC for closures gives a good example:
function replace_spaces ($text) {
$replacement = function ($matches) {
return str_replace ($matches[1], ' ', ' ').' ';
};
return preg_replace_callback ('/( +) /', $replacement, $text);
}
This lets you define the replacement function locally inside replace_spaces(), so that it's not:
1) cluttering up the global namespace
2) making people three years down the line wonder why there's a function defined globally that's only used inside one other function
It keeps things organized. Notice how the function itself has no name, it's simply defined and assigned as a reference to $replacement.
But remember, you have to wait for PHP 5.3 :)