🚀 go-pugleaf

hbaker@netcom.com (Henry Baker) writes:

>So, since the structure I was defining did not 'contain' a member of the
>class being defined,

Yes it did. The inner struct had a member of an incomplete type.

>class pair
>{class pair_rep {pair car,cdr;};
> pair_rep *rep;};                // Only needs to know sizeof(pointer).

Class pair_rep has members of type pair, but type pair is not a
complete type at that point in the source code. The problem is not
the pointer to pair_rep, but the definition of pair_rep itself.

Another example, without any cross-referencing:

class A;

class B {
    A a; // invalid, since A is not a complete type
};


It doesn't matter whether you use class B or not. Its definition
is invalid. The definition of class B must appear after that of
class A, or be removed entirely. In your example, you have to define
the nested class pair_rep after the definition of pair, not inside it.
--
Steve Clamage, stephen.clamage@eng.sun.com