[Haskell-cafe] (L)GPL libraries & Haskell/GHC (was: Re: ANNOUNCE: tie-knot library)

Nicolas Trangez nicolas at incubaid.com
Wed Dec 12 02:57:03 CET 2012


Note: IANAL

On Tue, 2012-12-11 at 17:45 -0800, David Thomas wrote:
> On Tue, Dec 11, 2012 at 5:35 PM, Brandon Allbery <allbery.b at gmail.com>wrote:
> 
> > (Oddly enough, GPL is not the only open source license.)
> 
> There was no implication to the contrary.  It was stated that BSD is a
> *weaker* license - this is true in the sense that it has fewer requirements
> (in particular, no copyleft) - and that "strong copyleft" licenses such as
> the GPL should be preferred as they do more to bolster the free software
> community.  You can disagree with this claim (there are arguments both ways
> - delving into them is not my point here) but please try not to bring in
> straw men.

Actually the library is made available under the LGPL-3 license,
according to its README, not the GPL (although the latter is implicit,
of course).

In the Haskell world this does have a different effect compared to when
one uses the LGPL for, say, a C library though, since (at least for now)
GHC uses/defaults to static linking, which IIRC (though IANAL) turns the
LGPL into GPL, so this has a severe impact for application authors. This
might be something people aren't aware of when releasing Haskell
libraries using the LGPL.

I tend to use the LGPL myself for most library-style projects, and do so
as well for Haskell code (although I'm aware of the drawbacks), but I'm
perfectly fine with people linking the libs statically as long as they
comply to the license "as if they were using dynamic loading".

If anyone knows some standard license which boils down to "obligations
like LGPL but OK for static linking as well", please let me know.

Nicolas




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