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In article 199603182248040068@msn.com, "Ron Burk" <RonBurk@msn.com> writes:
>I am having difficulty finding language in the draft
>that establishes the legality or illegality of the following:
>
>class Forward;
>
>class Any {
>    friend int Forward::SomeFunc(int SomeArg);
>    };

It is not valid. You cannot mention the name of a class member until the
class definition has been seen. To interpret the qualified-id A::B, the name
B must be looked up in the scope of A. If A has not been defined, the lookup
fails, and A::B must be considered undefined. Refer to chapters 3, 9, and 10
of the draft standard.

If this sort of thing were allowed, you could add members to a class
without modifying the class definition, thus violating the One-Definition
Rule.

---
Steve Clamage, stephen.clamage@eng.sun.com
---
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Ron Burk (RonBurk@msn.com) wrote:
: I am having difficulty finding language in the draft
: that establishes the legality or illegality of the following:

: class Forward;

: class Any {
:     friend int Forward::SomeFunc(int SomeArg);
:     };

: It certainly seems like a useful construct, and I don't
: see any impossibility in implementing it

Not enough of a lawyer to find it; however, the basic idea is that you can
not talk about the inside of something that has not been seen.  But I do
see some problems.  Let's add a little bit more from another thread
with discussion of a camel's nose inside of the tent.

class Forward::Node;  // also illegal
Forward::Node* ptr;
...
class Forward {
	private :
		class Node {
			// ...
			};
		int SomeFunc(int SomeArg);
	};

Now what?  You can not talk about a private nested class.  You can't call
a private member function.  Can you make it a friend?  What is the big
picture here?

Enjoy,
John
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