Question

Considering this basic code snippet:

<?
  class mcClassington
  {
        var $mcProperty='default';

        function mcDoSomething()
        {
               if($this->mcProperty == (/* new type of same class */)->mcProperty)
               {
                       sameBusiness();
               }
               else
               {
                       sortIt($this->mcProprety);
               }
        }
 }

Not sure how I can ask for a new object of whichever type the $this instance is.

I’m trying to write this function for a base class but let classes which extend from it check against their own default values. All I could think of was super-ghetto using switch(get_class($this)) but that would completely destroy the dynamic goal of the code I’m working on.

EDIT: So,.. I can’t actually post the complete real code. The best I can provide is a static example of usage posted below.

class displayObject //implements attachable
{
    public $layer = null;
    public $xPos = Array(
                        'left'=>null, 
                        'width'=>null,
                        'margin-left'=>null,
                        'margin-right'=>null,
                        'padding-left'=>null,
                        'padding-right'=>null
                    );
    public $yPos = Array(
                        'top'=>null,
                        'height'=>null,
                        'margin-top'=>null,
                        'margin-bottom'=>null,
                        'padding-top'=>null,
                        'padding-bottom'=>null
                    );
}


class Button extends displayObject
{
    public $link, $image, $backing;
    public $xPos = Array(
                        'left'=>null, 
                        'width'=>'120px',
                        'margin-left'=>'8px',
                        'margin-right'=>'8px',
                        'padding-left'=>null,
                        'padding-right'=>null
                    );
    public $yPos = Array(
                        'top'=>null,
                        'height'=>'108px',
                        'margin-top'=>'4px',
                        'margin-bottom'=>'4px',
                        'padding-top'=>null,
                        'padding-bottom'=>null
                    );
}

And then, in other files people might use the class like so:

$navBar = Array();  // Will hold basic Button Objects

$specialtyButton = new Button();
$specialtyButton->$xPos['width'] = '220px';
$specialtyButton->$yPos['height'] = '220px';
/*  and so on...    */

The function I’m writing must be called from within the base class displayObject in the format myFunction($this); What I’m trying to solve is sorting the pseudo-styles into different places based on whether or not they are the same as their default values.

For instance, $specialtyButton would be sorted specially because it’s width and height differed from Button’s default values but the Buttons inside $navBar would be overlooked because nothing was set explicitly.

Answer 1

You can simply:

$myClassName = get_class($this);
$newObj = new $myClassName;
if ($this->mcProperty == $newObj->mcProperty) {
  // ...

…but I wouldn’t. I would say it would be more sensible to hold the default values in a private property, so no-one can modify them, and compare against them instead. Creating new instances just to check if values are default seems like a horrible thing to do to me…