Markdown licensing

[european bob]

On Mon, 2004-12-13 at 12:00 -0500, John Gruber wrote:
> I've received a handful of emails from people working on non-GPL
> open source projects who would like to include Markdown.pl -- or PHP
> Markdown, which is also GPL'd because it's derived from the original
> -- with their projects, but feel they can't because of licensing
> issues. Most of these projects are BSD-licensed.

I think the PHP Markdown argument is the strongest one I've heard so far
(although I will note that there is nothing technically stopping you
distributing GPL'd code with BSD'd code, and the GPL doesn't somehow
infect the BSD code - so, I would suspect that the 'problem' people are
seeing isn't actually problem, but am willing to buy that they would
perceive it to be a problem ;)

> I've thought about this a lot, and I've come to the conclusion that
> the GPL and LGPL were written with the C family of programming
> languages in mind. E.g. their talk of "linking" a library as part of
> a greater whole. How does that apply to dynamic scripting languages
> such as Perl and PHP?

It's actually irrelevant I think; the linking stuff is a good-faith
attempt to describe the extent of derivative works. Whether or not
something actually is a derivative would be up to the courts, at the end
of the day. Although in the example of C, linking is something most
people would think is fairly obviously a derivative.

> I am not a lawyer. But I'd argue along the lines of what you're
> saying, Bob -- that calling out to the shell to run Markdown.pl is
> effectively using it as a standalone separate process. Hence, for
> this reason, I've granted free use of Markdown.pl to commercial
> weblog editing apps such as Ecto and MarsEdit. 

To be honest, I don't think you even needed to grant the permission in
the first place; the GPL allows them to do that. But, I think we're
agreeing ;)

> And at some point I ought to get around to turning my Perl version
> into a proper CPAN module, at which point single-licensing under the
> GPL might really get in the way for some people.

Indeed, and the FSF do ask that people writing Perl modules don't
licence singularly under the GPL (for example).

> I've been wondering about that, too. Thinking that perhaps I should
> "release" the syntax specification/documention under its own
> license. The idea being that I'd like to make the syntax freely
> available to anyone who wants to implement it, but if they want to
> call it "Markdown", they can't change it.

That would probably work, although we'd need a stricter definition of
Markdown :)

> I grabbed the "BSD" license used with SmartyPants from OSI's web site:
> 
> <http://www.opensource.org/licenses/bsd-license.php>

That seems ok. 

--bob.