I started using functions widely in an MVc framework. It began when Rails was released, and I thought, how could I copy the "helper" mechanism in a way that makes sense for PHP?

My answer was to use plain functions as helpers, at first because they could easily become Smarty modifiers, and later realized the function-only pattern worked really well across the whole app.

I write code like this...

# file: helpers/say_hello.php

    function say_hello ($params)
    {
        $to = $params['to'] ?: $params;
        return "Hello, {$to}!";
    }

Which is auto loaded by the framework and usable like this:

(PHP):

    echo say_hello('World');

(Smarty):

    {say_hello to="World"}