On Mon, Jan 11, 2010 at 2:08 PM, Don Stewart
sebf:
Hello Café,
when writing a Haskell library that uses two other Haskell libraries -- one licensed under BSD3 and one under LGPL -- what are allowed possibilities for licensing the written package? PublicDomain? BSD3? LGPL?
Libraries don't link in other things as such -- the .cabal file is the only thing that ties them together -- so you can use whatever license you like.
Any resulting binaries might contain a mixture of such libraries, and the most restrictive license will usually be the license of the result.
So, let's look at binaries then. In this case, LGPL is a problem. It requires you to offer a way to re-link such binaries against new versions/implementations of the library, which in practice requires it to be either open source or dynamically linked. Dynamic linking doesn't exist in GHC 6.10 and below. LGPL is thus restricted to open-source applications there. In 6.12.. well, dynamic linking exists, but in practice trying to replace a library implementation won't work. In fact, there's code in specifically to prevent it from working (well, crashing, really). So LGPL isn't very useful on that either. In practice, then, LGPL'd haskell libraries are probably useless for the stated purpose of supporting closed-source applications. You'd have to modify the license, or rather find something that fits better. I'm sure that exists, and chances are the author will be understanding if you ask. -- Svein Ove Aas