🚀 go-pugleaf

In article <3vofe6$3bs@galaxy.ucr.edu>, thp@PROBLEM_WITH_INEWS_DOMAIN_FILE
(Tom Payne) wrote:
> Henry Baker (henry.baker@wem.org) wrote:
> : Suppose I have the following nested class:
> 
> : struct pair
> : {struct pair_rep
> :  {pair car,cdr;};    // inner class has member of outer class.
> :  pair_rep *rep;};
> 
> : I understand the rule saying that a class cannot be a member of itself
> : [Stroustrup#2, page 545] (Bertrand Russell is now spinning in his grave ;-),
> : but I'm having trouble understanding why a _nested_ class cannot have a
> : member
> : of the outer class being defined.  This is especially irritating, since the
> : above is capable of being rewritten as [Stroustrup#2, page 645]:
> 
> : struct pair
> : {struct pair_rep;
> :  pair_rep *rep;};
> 
> : struct pair::pair_rep
> : {pair car,cdr;};
> 
> : Are compiler writers just being lazy, or what??
> 
> 
> It appears that the struct type  pair  is not yet defined at the point
> where it is used to delcare car and cdr.  (Note that sizeof(pair) will 
> not be known for another two lines.)  
> 
> In the revised version, when the struct type  pair  is used to declare
> car and cdr, it is already known that pairs consist of a single member
> called rep, which points to a structure of a thus-far undefined type
> called pair_rep.

So should I put down your vote in the 'lazy compiler writers' column?

I didn't hear any good reasons for not accepting the code as originally
written.

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