Re: How to make a non-GPL Org-mode exporter?

[Oleh Krehel <ohwoeowho@gmail.com>]

Andreas Hilboll <lists@hilboll.de> writes:

>>> Look here:
>>> https://en.wikipedia.org/w/index.php?title=GNU_General_Public_License&section=11#Libraries
>>>
>>> Most useful quote:
>>>
>>>> The Free Software Foundation (which holds the copyright of several
>>>> notable GPL-licensed software products and of the license text itself)
>>>> asserts that an executable which uses a dynamically linked library is
>>>> indeed a derivative work. This does not however apply to separate
>>>> programs communicating with one another.

>> thanks for this link and excerpt.  I could argue that the key word in
>> the excerpt is "executable".  I cannot see how code written in elisp
>> itself would need to be GPL.
>
> Exactly.  To quote again
> https://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL:
>
>    When the interpreter just interprets a language, the answer is no.
>    The interpreted program, to the interpreter, is just data; a free
>    software license like the GPL, based on copyright law, cannot limit
>    what data you use the interpreter on. You can run it on any data
>    (interpreted program), any way you like, and there are no
>    requirements about licensing that data to anyone.

Just to link the paragraph exactly below the one you quoted

> However, when the interpreter is extended to provide “bindings” to
> other facilities (often, but not necessarily, libraries), the
> interpreted program is effectively linked to the facilities it uses
> through these bindings. So if these facilities are released under the
> GPL, the interpreted program that uses them must be released in a
> GPL-compatible way. The JNI or Java Native Interface is an example of
> such a binding mechanism; libraries that are accessed in this way are
> linked dynamically with the Java programs that call them. These
> libraries are also linked with the interpreter. If the interpreter is
> linked statically with these libraries, or if it is designed to link
> dynamically with these specific libraries, then it too needs to be
> released in a GPL-compatible way.

Indeed, the Emacs interpreter gives "bindings" to all Emacs facilities,
which are GPL, and the interpreted program that uses them must be
released in a GPL-compatible way.

Plus Emacs supports byte compilation: someone could publish only the
exporter.elc, without providing exporter.el. That would be illegal, but
if the third party is given exporter.el released under BSD by a second
party, theoretically they could do it. Therefore, the second party
should not be allowed to change to BSD if they're linking to GPL code.

--Oleh