Hi Crista and Doug:

You have come up with different solutions for expressing negative
constraints on strategy graph edges (Crista has only 
one edge in strategy graphs).

Terminology mapping:
Demeter/Java	D

bypassing	bypass
only-through   	only

Doug allows to have either bypassing or only-through, while
Crista allows to have both. Crista even allows to have both
bypass and only for the same class.

I think what is needed is somewhere in between:

A{
  traversal t(V){
      {A->* bypassing {->A,f1,* ,
            	       ->A,*,D}
            only-through {->X,*,D}
      };
}                              

The above is useful but to allow both bypassing and only-through
for the same class seems not needed. Example:

A{
  traversal t(V){
      {A->* bypassing {->A,f1,*} 
            only-through {->A,*,D}
      };
}                              


What is your position on this?

-- Karl
PS. I like "only" better than "only-through". "only" is a negative
constraint; "only-through" sounds positive.