PHP: Replacing default array with user defined array? (replace/combine)

Question

I am writing a small framework for myself to help build my site, my current example is an object function to start an HTML page, it will be ran like this:

$page->head(array(
    'doctype' => 'html4',
    'description' => 'My page'
    //etc
));

I wish to have a default array (as defined in head()) to have default values in case they are not defined. It may look like this:

$defaults = array('doctype' => 'html5', 'author' => 'default', ...);

What would be the best way to replace each default element with one defined in the head function's arguments when called?

I found something maybe like this, being unsure of what it exactly does but it has the right idea http://www.php.net/manual/en/function.array-replace.php#94458

Answer 1

It sounds like you may be able to do this with array_merge, like this:

$page->head(array_merge($defaults,array(
  'doctype' => 'html4',
  'description' => 'My Page'
  // etc
)));

This will overwrite any value from $defaults with the new value, while preserving any key that does not have a new value.

Answer 2

Is there a reason that you're not using classes for this? It sounds exactly like a problem that would benefit from OOP. For example:

class PageHeader
{
    private $m_sDoctype;
    private $m_sDescription;
    // other member vars, such as an array of css files

    function __construct($doctype, $desc)
    {
        // set your default values
        $this->m_sDoctype = _isset($doctype) && $doctype != null ? $doctype : 'html4';
        $this->m_sDescription = _isset($desc) && $desc != null ? $desc : 'My Page';
    }

    function render()
    {
        // dump out html however you see fit
    }
}

class BasePage
{
    private $m_oPageHeader;
    // other member vars

    function __construct($doctype, $desc)
    {
         $m_oPageHeader = new PageHeader($doctype, $desc);
    }

    function render()
    {
        $this->m_oPageHeader->render();
    }
}

index.php (or whatever your homepage is):

var $page = new BasePage(null, 'Home Page');
$page->render();

A couple notes:

1. This is a very simplistic example that I haven't tested
2. I know that this isn't really what you were looking for (as you were looking for a solution to your array problem), but I were developing a small framework for myself, this is definitely the way I'd go about doing it as there are clear benefits to using OOP in any environment.

Edit: I forgot to mention that, by using constructors with default values, you get the desired functionality of having the defaults, but also having the ability to overwrite them.