Question

I’m sorry, I know this is a very simple question but I’ve search here on SO and tried to let Google be my friend to no avail.

I’m wondering what a variable assignment as an argument to a function does in PHP. Specifically, I found this example in the Codeigniter documentation:

public function get_news($slug = FALSE)
{
    if ($slug === FALSE)
    {
        $query = $this->db->get('news');
        return $query->result_array();
    }

    $query = $this->db->get_where('news', array('slug' => $slug));
    return $query->row_array();
}

Basically, this is a method of a controller class which is supposed to take any request to the controller “News” that has an argument and query the db to see if a news item with a slug matching that argument exists.

My guess is that this initializes the variable $slug to FALSE but then if an actual “slug” argument to the method is being passed by the user, that FALSE value is immediately overwritten before the value is passed to the function, but I can’t find information about this anywhere.

Thanks for your help!

Answer 1

http://php.net/manual/en/functions.arguments.php

A function may define C++-style default values for scalar arguments as
follows:

The variable is defaulted to whatever is set in the argument if nothing was passed in, like in c++.
If you give no value for the argument, it uses the default you defined.
Any value you pass in for the argument overrides the default argument.