Re: E-LISP licensing question

[Glenn Morris]

Geoffrey Teale wrote:

> If I write some emacs lisp code does the way emacs deals with that code 
> at runtime mean that the code must always be under the GPL?
>
> Or to put it another way...
>
> Does doing (require 'foo.el) link the code into emacs in such a way that 
> foo.el must be licensed under the GPL.

I don't really know, but this seems like an important question that
should have a clear answer.

This GPL FAQ seems very relevant, if we consider Emacs as an
interpreter for the Emacs Lisp programming language:

http://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL

   If a programming language interpreter is released under the GPL,
   does that mean programs written to be interpreted by it must be
   under GPL-compatible licenses?

I think it's clear that you don't need to license under the GPL
specifically. But you may need to use a GPL-compatible license.

Trying to interpret the answer to that FAQ, it would seem that if you
just write some "pure" Emacs-lisp, you can use whatever license you
like. But if you use any GPL'd elisp libraries, then you need to use a
GPL-compatible license. This raises the question of what we consider
part of the Emacs lisp "language", and what we consider an "extension"
provided by a "library". Perhaps anything not dumped with Emacs is a
"library"? Which means that the requirements could change if a package
starts to be dumped with Emacs...

Can someone give a clear answer to this question?