Re: Emacs contributions, C and Lisp

[Richard Stallman <rms@gnu.org>]

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  > This illuminates the central question at hand:  if an Emacs plugin is 
  > GPL, and provides access to internals of GCC, which is also GPL, can 
  > nonfree software use that Emacs plugin?

"Use" is too broad a word; such a broad question has no answer.

Nonfree software can't be _combined_ with GPL'd code, which includes
that plug-in (what the plug-in _does_ is beside the point).  If a
program A "uses" a program B, does this mean the two are combined?
That depends on details (and there may be a gray area; also, we can't
be sure where courts will say the border is).

What I am pretty sure of is that if the plug-in generates the AST as
text, a GPL-covered program could write it into a file, and some
separate proprietary program could read the file, and this would not
be considered combining the two programs.  It would be lawful, and
could be quite harmful.

This is why there is danger in generating the AST as text.

-- 
Dr Richard Stallman
President, Free Software Foundation
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