struct environment

[Andrew Cagney]

> Well, sort of.  It won't be a DAG necessarily (I think that mutual
>> >"using" statements are legal in C++; I remember a GCC bug involving
>> >them was fixed not long ago), and it will be somewhat complicated
>> >figuring out which ones to look up (namespace links are different than
>> >block scope links).
> 
>> 
>> Don't forget that GDB doesn't need to model the language.  Just the 
>> namespace behavior at a given PC.  The effect of "using" would be to 
>> just grow a nametab in someway.
> 
> 
> This is legal C++:
> 
> namespace D {}
> 
> namespace C { 
>   using namespace D;
>   int x, y;
> }
> 
> namespace D {
>   using namespace C;
>   int x, z;
> }
> 
> If using just grew a nametab we'd get into a great deal of trouble.

Depends on how you grow it :-)  Something like (assuming a real language 
:-):
	D:
	0: x, z
	1: x, y (from C)
	2: ...

Andrew