Re: E-LISP licensing question

[Stefan Monnier]

>> 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?

AFAIK, you can't write usable Elisp code which isn't one way or another
linked to GPL'd code.  The only way to do that would be to write the
code in basically the intersection of Elisp and CommonLisp, which
precludes operating on buffers, files, etc...

Of course that's only true so long as the only Elisp implementations are
all GPL'd.


        Stefan