Crisis Averted!: PHP 5, static and inheritance

No title

Matthew Grdinic (http://www.sledxchange.com) — Tue, 18 Dec 2007 16:57:33 -0800

^ oops

http://blog.felho.hu/what-is-new-in-php-53-part-2-late-static-binding.html

Web Developer

Matthew Grdinic (http://www.sledxchange.com) — Tue, 18 Dec 2007 16:55:12 -0800

php 5.3
Late Static Binding

Supposed to be out early 2008.

Re: No title

Brett (http://socket7.net) — Mon, 03 Dec 2007 13:12:18 -0800

Thanks for pointing this out Ben. There is hope!

No title

Ben (http://www.benlog.org) — Sat, 01 Dec 2007 19:43:59 -0800

PHP bug #42681 - status is 'assigned'.

If the class is instantiated

James — Wed, 28 Nov 2007 00:43:48 -0800

blah

propertyDefinitions = self::$propertyDefinitions;

// propertyDefinitions);

However I doubt this is the best solution. There should be the ability to do
$className::whatever without eval or something :/

Alternative to Tom's method

toby (http://bezoe.com) — Mon, 22 Oct 2007 01:03:37 -0700

I've used this method for getting a calling subclass's class constants. The problem is that the interpretor will not catch syntax errors in the eval until the statement is executed.



$className = get_class($this);

return eval("return $className::table;");

Possibility

KEM — Sat, 18 Aug 2007 20:34:31 -0700

this has been irking me for a while.

anybody know if you can catch "method undefined" errors with set_error_handler? no luck yet... i'm not exactly sure what kind of error that is. it may not be "catchable".

dirty, but (hypothetically):

<?php
	function myErrorHandler($errno, $errstr){
		$info = debug_backtrace();
		// if called on a subclass of Record, divert to a call to 
		// Table::find with the correct $table argument
	}
	set_error_handler('myErrorHandler');

	class Table {
		public static function find($table){
			// ...
		}
	}
	
	// dummy
	abstract class Record {}
	
	class Person extends Record {
		public static $table = 'People';
	}
	
	Person::find();

?>

that would keep the classes nice and clean…

Re: My solution

Brett (http://socket7.net) — Sun, 15 Jul 2007 19:41:08 -0700

I like your solution for its brevity. I also like that for each new class it's only a small method to implement; it's very well contained. I've never liked my solution of passing variables around like a fool; that's incredibly messy.

Thanks for sharing.

My Solution

Tom Lancaster (http://www.newhanoian.com) — Wed, 11 Jul 2007 22:25:42 -0700

static $table;

 protected function table() {
	$vars = get_class_vars(get_class($this));
	return $vars['table'];
}

Exactly the same problem

Jonovic — Mon, 09 Jul 2007 11:43:02 -0700

This is realy pain in the a.. My solution for this time is to turn to dynamic objects and forget the static classes for a while. I have been working around the database access objects with the help of design patterns.

Re: Workaround?

Brett (http://socket7.net) — Sat, 05 May 2007 14:54:34 -0700

I worked around it in two ways, neither of which are great. One of the ways is to set a member variable in the constructor. This makes the value available within the object as well as from the outside, though it is not static. Obviously not a great solution.

The second way I've worked around this is to pass an extra class name parameter into the static method calls telling the method which class it should 'act as.' Again, not a great solution.

If you're willing to put up with the lack of purity, these two options work well enough. Hopefully some future version of PHP will address this.

Workaround?

Tom Lancaster (http://www.newhanoian.com) — Wed, 02 May 2007 22:20:27 -0700

I'm having this exact same problem. In my case I'm subclassing an abstract actsastree for different db tables. Of course I have the table name as a static member, and of course it doesn't work.

I'm interested to know how you work around this.