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[2008-01-14 20:15 UTC] ms419 at freezone dot co dot uk
Description:
------------
I understand that, unlike some other languages, PHP does not support overloading: I can't implement two functions with the same name but different signatures. However I can simulate overloading using func_get_args() and testing with which arguments the function was called.
Now what I want is a function which can be called either as an instance method with no arguments, or statically with one argument: an instance of the class. I test whether the function was called statically or not using isset($this)
However in PHP5, this produces an error:
Non-static method BaseTaxonomy::getTerms() should not be called statically in...
Like it is possible to simulate overloading in PHP without generating errors, I wish it were possible to define a function which can be called either statically or as an instance method, without generating errors.
Much thanks, Jack
Reproduce code:
---------------
Toy example:
class BaseTaxonomy
{
protected $terms = null;
public function getTerms()
{
if (!isset($this))
{
$args = func_get_args();
return $args[0]->terms;
}
return $this->terms;
}
}
Actual result:
--------------
Non-static method BaseTaxonomy::getTerms() should not be called statically in...
PatchesPull RequestsHistoryAllCommentsChangesGit/SVN commits
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Last updated: Fri Apr 19 05:01:29 2024 UTC |
Actually, you must declare your method static. It will not produce any warning, but you will cannot be able to use $this. Instead, you must always use the first parameter. So this will be like this: <?php class MyClass { static public function MyMethod() { $this = $Instance = func_get_arg(0); if ( ! $this instanceof self ) { throw new Exception('You must use this method with an Instance of the same class.'); } /* ... your code here ... */ } } ?> Remember.. You will always need to pass the instance for your method to work correctly. Farewell.Since PHP does actually distinguish between static and non-static methods, it makes no sense (as external interface) to disallow _both_ calling the same method as static and non-static _and_ having same-named static and non-static methods. At run time PHP knows if you're calling a static or a non-static method, so it can pick the correct one. Here is an example where same-named static and non-static methods might make sense: class Foo { static public function defaultInstance() { static $instance = null; if (is_null($instance)) { $instance = new self(); } } static public function bar() { $instance = self::defaultInstance(); return $instance->bar(); } public function bar() { // do something } } Foo::bar() // no need to explicitly request the default instance $f = new Foo(); $f->bar() // but now it is clear that we're doing the same thing with a specific instanceRegarding the last comment, PHP cannot allow a static and non-static method with the same name, because this would create an ambiguity between static calls and scoped instance calls. Consider: class A { public function method() {} public static function method() {} } class B extends A { public function test() { parent::method(); } } Current parent::method() is a scoped instance call to non-static A::method(). Think of it as doing $this->method() but forcing a scope of "parent". If there could be a static and a non-static method with the same name, parent::method() could also refer to a static call to static A::method(), thus causing an ambiguity. In either case, the "you can call a method either statically or not" functionality is on the way out, so I'm closing this as Won't Fix.