possible readline license problem with ghc and -package util

Simon Marlow simonmar@microsoft.com
Tue, 11 Jun 2002 16:18:53 +0100

> I have a problem with the readline license that applies to ghc, and
> programs compiled with ghc.
> The readline library is under the GPL license. This means that any
> program (including ghc) that links with this library must itself be
> licensed under the GPL.


Yes, you're right.  I hadn't noticed that readline was GPL and not LGPL.

The BSD license is "compatible" with the GPL, so according to the FSF, =
just because GHCi is linked with readline doesn't mean we have to =
license the whole of GHC and its libraries under the GPL.  But we do =
have to make GHCi "available under the GPL" whatever that means.  =
Actually I'm dubious about the notion of compatible licenses - I read =
the GPL carefully and I still don't see how it is compatible with the =
BSD license at all (I'm not the only person to have noticed this, see =
for example http://www.kallisys.org/bsd-lite/bsd-gpl/?lg=3Den).

I think realistically we have to ditch readline for GHCi and use =
something with a friendlier license.  BSD's libedit is a possibility.

As for the readline library that GHC provides, I think that will have to =
move into its own package: we knew we would have to start a separate =
package for GPL libraries at some point, it looks like we've reached =
that stage.

This is *so* annoying when all we're trying to do is write free software =
here.   Grrrr.