Integrating editline with ghc

Manuel M T Chakravarty chak at
Thu Jan 17 20:13:20 EST 2008

Alex Young:
> Yitzchak Gale wrote:
>> Isaac Dupree wrote:
>>> GHC is in no legal trouble whatsoever... only if proprietary Haskell
>>> code uses the readline library and doesn't switch to using the  
>>> editline
>>> backend.
>> Agreed. I didn't mean that GHC itself was ever in any
>> legal trouble. But as a compiler, it must be possible for
>> users to compile with it without getting into legal trouble.
> Yes.  I'm still learning Haskell, and it's my intention to use GHC  
> to produce commercial plugins for an application on Windows (and  
> possibly OS X, haven't decided yet).  This whole discussion makes me  
> worry - not because I have any intention to break any licences, but  
> because I might do so by accident.  At this point in my learning,  
> I've got no idea what will cause "problem packages" (problems from  
> my point of view being ones that cause a phone call to a lawyer) to  
> be linked in to my binaries.  It would be enormously helpful if  
> there was a wiki page somewhere that said "To use GHC/mingw as a  
> compiler for commercial software, it's likely you want to avoid  
> these modules and command-line flags" or alternatively "To guarantee  
> that no LGPL or GPL libraries are linked, use these flags".
> The last thing I want is to cause myself extra work when someone  
> chucks my plugin through a hex editor, sees a whole load of GMP  
> symbols (for example) and demands some form of compliance that  
> commercially I'd rather avoid.

The Haskell package system Cabal has a package description format that  
includes an entry stating the packages license.  You can browse  
packages at

and the package entries include the license field.  For example, the  
entry for readline

says it is GPL'ed - ie, you may not link it into proprietary code.

I agree that a wiki page explaining this and the situation with static  
versus dynamic linking of LGPL'ed code would be helpful.


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