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Subject: Re: [PHP-DEV] Order of	class	resolution	with	namespaces	and	autoload
From: stas@zend.com (Stanislav Malyshev)

> Yes. I think that if you use an unqualified name it should always be 
> relative to the namespace (and importing internal classes into your 
> namespace lets you use short names for them, avoiding ::Exception).

Unfortunately, there are problems with this solution, since it
makes common case harder to implement - internal classes are more 
frequently used than overridden. It makes harder to convert library code 
which does not use tricks like overriding system classes - which is on 
my experience most of the code - you have now to go to almost every file 
and find all the system classes you have used there and put imports for 
them.

> To me, this is unpredictable because include order changes how otherwise 
> identical code behaves.

It is entirely predictable, and you know the rules that would allow you 
to predict it.

> I can solve this in my case by always writing import Test::Exception;. 
> However, if I really want to use the builtin Exception class, it seems 
> like I _must_ type it as ::Exception every time - which is something you 
> wanted to avoid as well as I.

If you really want to use internal class, why you define and include 
non-internal class with the same name? Moreover, your own proposal above 
says that's what you have to do - write ::Exception or import. So either 
you want unqualified internal names to work or you don't?

> Other options I tried:
> 
> import Exception;
> -> name conflict, which seems correct

import Exception is a no-op, so I don't understand how you could have 
got name conflict. Do you mean "import Test::Exception"? That should 
work, if it didn't it's a bug.

> import Exception as Error;
> -> Fatal error: Import name 'Error' conflicts with defined class in 
> /Users/chuck/Desktop/php namespaces/2.php on line 4
> (this I don't understand)

I'm afraid I am missing something since in line 4 of 2.php there's no 
definition of any class or import. Can you give me full examples of 
non-working parts? It might be there's some bug in there.

> import ::Exception as Error;
> -> parse error (can't import a top-level class name that way)

Well, we might allow importing global classes, if it's needed.

> Therefore, in my mind, in order to write durable code that will not 
> break no matter what other classes other developers define or import, I 
> should always prefix builtin classes with ::.

Other developers shouldn't define or import classes into your namespace...

> Given this, the only difference between how I think things should work 
> is that I think that, when I have declared a namespace, I should be able 
> to rely on any short name referring to that namespace or one of my 
> explicit imports. The key being that _I_ declared that namespace and the 

Well, I think restricting namespaced code's access to internal classes 
is not a good idea, since internal classes are rather frequently used.

> imports and they will affect only that file, so I am completely in 
> control of what name means what.

You can control it anyway, you just have to be a bit more explicit now.
-- 
Stanislav Malyshev, Zend Software Architect
stas@zend.com   http://www.zend.com/
(408)253-8829   MSN: stas@zend.com