[Haskell-cafe] [Cabal-devel] Cabal && license combinations

Chris Smith cdsmith at gmail.com
Thu Feb 10 17:04:30 CET 2011

On Thu, 2011-02-10 at 08:59 +0100, Ketil Malde wrote:
> I disagree - the linked executable must, but not the wrapper by itself.
> It's source code, i.e. text, thus a creative work, and therefore
> covered by copyright - on its own.

You're certainly right from a legal standpoint.  But being right doesn't
actually matter.  The instant anyone actually compiles an application
that uses your library, however indirectly, they are bound by the terms
of the underlying library as well.  So your bindings are effectively
covered by the underlying license anyway (unless you're choosing a
license for the sake of people who will never produce any usable end

Sure you could attach yet another license; but unless you deliberately
intend to be even more restrictive, there's no reason whatsoever to
license the thin bindings layer differently from the library it is
binding to.  Doing so would just be potentially misleading people about
the licenses they need to comply with, especially when the bindings are
to libraries that are not packaged with Cabal and do not have a uniform
place to record their license terms.

> So this may be a problem for distributions, which ship compiled and
> linked binaries.  But generally not for authors, darcs repositories or
> Hackage, which only ship source code.

Of course it is a concern for authors!  Do you really think authors
write libraries, and then just don't care whether potential users can
actually use them?  If you don't expect anyone to ever link a program,
even indirectly, against your library, then you probably shouldn't have
bothered distributing it; but if you do expect that, then you typically
make choices when developing an application based on what rights you
want *those* people to have.  The reasonable expectation in Haskell is
that they'll probably statically link; and you should read licenses of
your dependencies, and carefully choose dependencies, accordingly.

Chris Smith

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