[Haskell-cafe] Re: Hmm, what license to use?

Brandon S. Allbery KF8NH allbery at ece.cmu.edu
Sat Sep 27 12:57:00 EDT 2008

On 2008 Sep 27, at 11:59, Simon Marlow wrote:
> Magnus Therning wrote:
>> Wolfgang Jeltsch wrote:
>>> Am Freitag, 26. September 2008 09:24 schrieb Magnus Therning:
>>>> Recently I received an email with a question regarding the  
>>>> licensing
>>>> of a module I've written and uploaded to Hackage.  I released it  
>>>> under
>>>> LGPL.  The sender wondered if I would consider re-licensing the  
>>>> code
>>>> under BSD (or something similar) that would remove the need for  
>>>> users
>>>> to provide linkable object files so that users can re-link programs
>>>> against newer/modified versions of my library.
>>> Since GHC does cross-package inlining, code of your library is  
>>> directly included (not just linked) into code that uses the  
>>> library.  So I think that every code that uses your library will  
>>> have to be released und the GPL or LGPL which is a very bad  
>>> situation.
>>> People, don’t release Haskell libraries under the LGPL!
>> That would be serious indeed, but before changing my ways I'd need  
>> more
>> information to back up your statement.  Could someone confirm that  
>> code
>> from one installed module can be inlined into another?
> When optimisation is turned on, you have virtually no control over  
> how much code GHC will copy from one module to another, which is why  
> several people (me included) have expressed concerns about the use  
> of an unmodified LGPL with Haskell code in the past.  I believe at  
> one stage we even asked for clarification from the FSF, but I don't  
> recall getting an answer.

As for confirmation, try ghc --dump-iface on a .hi file, often you  
will see GHC Core in the .hi
so that it can be inlined in modules importing it.

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH

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