[Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)

[Matthias Kilian]

Hi,

On Fri, Mar 05, 2010 at 01:16:18AM +0300, Bulat Ziganshin wrote:
> >> [...] The SFLC holds that a
> >> library that depends on a GPL'd library must in turn be GPL'd, even if
> >> the library is only distributed as source and not in binary form.
> 
> > Was this a general statement
> 
> yes. it's soul of GPL idea, and it's why BG called GPL a virus :)

Oh, BSD3 or ISC licensed code is viral as well, but only on the
source code level ;-)

(if you redistribute the sources, you have to leave the license and
the copyright marker intact)

Anyway, I really think the SFLC people are telling lies here (or,
as someone else wrote in this thread, are telling what they whish
the GPL to imply).

Applying some common sense tells me: If you write some code (library
or program) that depends on  some GPL licensed library, you can
still redistribute your *source code* under whatever license you
want, as long as your source code distribution does not contain
copies (original or modified) from the GPL'd stuff it depends on.

For binary products created from such a library combo, you have to
apply the GPL, which should be fine if *your* code is BSD3 or ISC
or something similar. But nobody can force you to apply a specific
license to your *source code*, even if the binary (links against/calls
functions provided by) a GPL'd library.

Oh, and for the discussion about wether APIs may be license-worth, which
also popped up in this thread;

	/*
	 * Copyright (c) 2010 Matthias Kilian <kili at outback.escape.de>
	 *
	 * All rights reserverd.
	 */
	extern int foo(double bar);

If you ever dare to write some C function `foo' that takes a double and
returns an int, I'll sue you to death ;-)

Yes, there are APIs more inventive than that example above, but
they're just *interfaces*. There has to be a lot of brain used on
some interface to make it a creative work. (Oh, monads jump to mind)

Ciao,
	Kili