Making some Objects in PHP

gistfile1.php

<?php


/*
 * Send all required arguments.
 */
$test = new My_Object( array(
	'one'   => 1,
	'two'   => 2,
	'three' => 3,
	) );

print '<pre>'; 
gettype( $test );  // Should be "My_Object"
var_dump( empty( $test ) ); // false as expected.
var_dump( $test );
print '</pre>';



/*
 * This object is missing one required argument.
 */
$test = new My_Object( array(
	'one'   => 1,
	'two'   => 2,
	) );


print '<pre>';
gettype( $test ); // Would be neat if this could return some sort of error object.
var_dump( empty( $test ) ); // Even though all properties have been removed, this still returns false?
var_dump( $test );
print '</pre>';


class My_Object {

	public $one   = null;
	public $two   = null;
	public $three = null;
	
	public function __construct( $args = array() ) {

		$diff = array_diff_key( get_object_vars( $this ), $args );

		if ( ! empty( $diff ) ) {
			
			/* Let them know they're doing it wrong. */
			trigger_error( 'Could not construct object.' );
			
			/* It's possible to kill all of the properties. */
			foreach( array_keys( get_object_vars( $this ) ) as $property ) {
				unset( $this->$property );
			}
			
			/* Anyway to change type of object before return? */
			return;
		}

		$this->one   = (int) $args['one'];
		$this->two   = (int) $args['two'];
		$this->three = (int) $args['three'];
	}
}

Actually, I did just find some reference to using settype( $this, 'null ); as a deconstructor for objects. You might be able to use a similar setup inside __construct() to re-cast your object as an error object, as null, as a Boolean, or whatever. But I can't test at the moment on this machine ...

Thanks for the feedback! I'm kind of in this named argument phase and I don't see it going away anytime soon quite honestly. I fear ever having to read documentation again just to know the purpose of the values that I'm passig to a function. Makes me angry :) ... or :( ... yeah, that's more like it.

I thought about doing #1. And this is what I will probably do in the end. Just thinking about alternative to doing this, but it really makes a lot of sense.
#2 really has no effect. Although I did not see it stated in the docs, I think that __constructor() returns void. Anything that I've tried along these lines has failed. I can never access the return value.
#3 This is pretty cool - I did not know that that function existed. Will definitely come in handy in the future! Unfortunately, it's a bit strict as it stops the script. Would much rather generate a notice and let the script continue.

settype inside the constructor did not seem to do anything ... started to get excited about this one, but no luck.
#1 is the winner so far!!!

I also had another idea and was wondering what you thought:

What if I were to create a boolean static method named check_args(). This could be called on the args before individual objects are created?

What if I were to create a boolean static method named check_args(). This could be called on the args before individual objects are created?

Kind of like pre-validation? I think that would work ... but you'd need to document it well so others using the code would remember to use it before they instantiate their object.

if ( My_Object::check_args( $args ) ) {
    $test = new My_Object( $args );
} else {
    // die in fiery brillaince
}

Cool! Other people using the object is totally not permitted. My intention is to only use it internally in a plugin. Basically there would be a configuration array for "Icon Sets" that is filterable. This array would be looped over and a new Icon_Set object will be created only if it is configured properly.

I meant "others using the code" as in anyone who forks your project or uses it as a base/inspiration for their own system.

Now that I know what you're trying to do (rather than mucking around with My_Objects and $tests), have you considered using a factory method?

Basically:

$test = create_my_object( $args );

function create_my_object( $args = array() ) {
    if ( Icon_Set::check_args( $args ) ) {
        return new Icon_Set( $args );
    } else {
        return new My_Error( "You're doing it wrong!" );
    }
}

Then $test will either be an instance of Icon_Set or some custom error object if it was configured improperly.

(OK, it's not a real factory method ... but similar enough ...)