Meta-Level Compilation project / Introspector/ AST access / Licensing question

[Joe Buck]

James Michael DuPont write:
> <<> There is nothing legally stopping anyone from creating
> > a non-free back and front end on the gcc, if you dont
> > use linkage, but file format.

I said:
> Correct.

Robert Dewar writes:
> Please do not assume that this is a correct legal theory. It is not at all
> clear that using files makes much difference from a legal point of view.

I should have been more careful when I wrote "Correct."  Should GCC accept
patches to provide a standard interface that reads and writes compiler
internals in XML format, with documentation, then it would be hard to
argue that all readers and writers of the format would need to use GPL
licensing, because use by external programs would be *intentional*.

As Robert points out in more detail, courts can do anything.