Edit report at https://bugs.php.net/bug.php?id=40837&edit=1
ID: 40837
Comment by: billco at fnarg dot com
Reported by: nick dot telford at gmail dot com
Summary: static and non-static functions can't have the same
name
Status: Not a bug
Type: Bug
Package: Class/Object related
Operating System: Irrelevant
PHP Version: 5.2.1
Block user comment: N
Private report: N
New Comment:
My thoughts echo those of dmittner, while I think we all acknowledge the need
for parent::method() functionality, I don't see why that small detail should
invalidate this popular feature request. This seems like a limitation borrowed
from C++, where it was a necessary evil of supporting multiple inheritance.
PHP does not have MI and thus there was never a need for such a contrived
"scope resolution" operator when something like Java's "super" would have
sufficed.
I can recognize that its usage dates back to the very beginning of PHP OOP, and
it would be problematic to change the :: operator with all the existing code
out there. Why can't we choose a new operator for pure static calls and get on
with it ? It sounds like that would allow same-named static methods without
ambiguity, while allowing the :: operator to continue as-is.
Previous Comments:
------------------------------------------------------------------------
[2013-04-21 18:57:01] dmittner at llnw dot com
@ni...@php.net:
While what you write is all technically correct, I think it comes down to this
being the problem:
":: is not a "static access operator", it's a "scope resolution operator". It
calls a method (or accesses a property) in a certain scope."
Conceptually that one operator is trying to do too much. That "certain scope"
it's trying to use isn't chosen by the programmer; it's chosen by the context;
by where it's being used. That's presumptuous and an unnecessary limitation.
"::" is (AFAIK) the only way to access specifically static resources in one
context, but then is also used to reference the resources of special names in
other contexts.
Clearly people want to be able to call the same method name in both an object
and static scope. It's the same reason people like function overloading: they
have logic that accomplishes the same goal but done differently--this time
based
on scope. And we'd rather not dirty our code with resource names named
differently just to identify scope.
If the :: operator can't consistently serve this purpose because it's also
having to accommodate "parent" and other special names, then maybe we just need
a new operator specifically for calling methods in a static scope and ONLY for
doing that.
The more I think about this the more I think :: is just broken because it's
treated inconsistently. There's probably good reasons I'm not thinking of, but
it seems :: could have always meant "static scope" and "->" could have always
meant "object scope"; and "parent->resource" would have been valid right
alongside "parent::resource", each accessing the parent's resource in
legitimately different scopes.
So leave :: as it is for backwards compatibility.
Add support for "->" on special names for object scope and a new operator
specifically for static scope. Then we'll be able to define both object-scope
and static-scope versions of the same resources and we'll have operators to
access each consistently.
Ultimately it's not a huge deal. It'd just be nice to be able to use the same
names in both scopes. But we can at least achieve the functionality for now by
naming everything "$staticVariable" and "staticMethod()". It's just really
gross.
------------------------------------------------------------------------
[2013-04-21 09:40:32] ni...@php.net
We *can not* have static and non-static methods with the same name. This is
*not* just a backwards compatibility concern.
I think the issue here is that you got the meaning of the :: operator wrong. ::
is not a "static access operator", it's a "scope resolution operator". It calls
a method (or accesses a property) in a certain scope.
E.g. Foo::bar() calls the method bar() in the scope of class Foo. bar() here
can be any method.
A "static" method just means that the method does not need $this. The
Foo::bar() call will only work if
a) the method is static or
b) the method is non-static and we have a $this.
The distinction between "static access operator" and "scope resolution
operator" is important and helps you understand why some things are as they
are. For example, if you want to access a parent method, then what do you write?
parent::foo(). This means that you call foo() in the parent scope.
I get that people might argue whether "calling non-static methods with ::" is
useful in the general case, but calling parent methods is something everybody
should understand and find useful. And using that example it's also easy to see
why you couldn't have the same static and non-static method. Consider this
small example:
class A {
public function foo() { echo 'non-static'; }
public static function foo() { echo 'static'; }
}
class B {
public function bar() { echo parent::foo(); }
}
(new B)->bar(); // What do you get?
Allowing static and non-static methods of the same name would require us to
completely change the concept of scope-resolution and find a different way to
call parent methods etc.
So, just to say it again: Removing "::"-calls to non-static methods is *not*
just a backwards compatibility issue, it would also cause problems with other,
currently used and encouraged language features.
Another thing that might help the understanding (apart from interpreting :: as
scope-resolution) is not seeing static and non-static methods as distinct
method types. Rather they are the same and "static" is just another method
modifier like "public" or "final":
You probably wouldn't ask to have "an abstract method and a final method of the
same name", right? Asking for a non-static and static method of the same name
makes similarly little sense. "static" just means "doesn't need $this" and
nothing more.
On a related note, this "static" modifier is also available for closures (i.e.
you can write "$foo = static function() { ... }") and also means the same
there, that the closure does not need $this. Prefixing a closure with "static"
does not make it some kind of wholly different function type, it's just a
modifier. Same for the static methods ;)
I hope things are a bit clearer now.
------------------------------------------------------------------------
[2013-04-21 05:30:23] dmittner at llnw dot com
I've got to add my vote to this feature.
My use case consists of data validation methods. If called statically the
validation tests are limited to things like string length, contents, etc. If
called on an object it would include those tests (probably calling the static
form of itself) and also comparative tests to other object conditions.
I sympathize with backwards compatibility but sometimes you have to push
forward. Case and point, some people I know are working with a Java-based
system
that doesn't support Java 7, so when building new servers they have to
explicitly install an older version. Cutting a line between major PHP versions
seems similarly viable.
I'd also cite Magic Quotes which are completely removed in 5.4, which could
similarly break older PHP4 compatibility. The precedent is set.
Failing all that, how about a configuration option?
------------------------------------------------------------------------
[2012-11-20 02:13:10] capitaine dot gloumi at gmail dot com
The "backward compatibility" should set to deprecated any static call of object
method, and use it IF NO static method with the same name exist.
I use static method and object method with same name in lot of paterns, it's
useful in lot of case.
------------------------------------------------------------------------
[2012-11-19 03:27:35] ahar...@php.net
If a class is namespaced, by definition it isn't PHP 4 compatible.
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
https://bugs.php.net/bug.php?id=40837
--
Edit this bug report at https://bugs.php.net/bug.php?id=40837&edit=1
