[computer-go] Collaboration project. Once again

[Ross Werner]

On Sat, 5 Aug 2006, Jeff Nowakowski wrote:
> On Sat, 2006-08-05 at 08:48 -0600, Markus Enzenberger wrote:
>> GoGui can be used with any Go engines, independent of their license, as long
>> as the interface and tools that come with GoGui communicate with the Go
>> engine only by using the GTP protocol.
>
> This then is special permission given by you that is not given by a
> straightforward reading of the GPL license.  Imagine that you distribute
> your program with GoGui as the main interface.  Is this not a derivative
> work?

It depends if it communicates over a standard interface. The GTP protocol 
is definitely a standard interface, therefore this would not be in 
violation of the GPL or require any "special permission".

For example, if you have a program that communicates via standard SQL, and 
there are multiple databases that can be used, then even if you distribute 
your program with a GPL database, your program is not a derivative work 
because you could just as easily remove the GPL'd database and use a 
BSD-licensed database or a proprietary-licensed database.

Now, if your program does not speak standard SQL, but actually *requires* 
the use of a specific (GPL'd) database, then we're in a murky legal area 
where Stallman believes your program is required to be GPL'd in order for 
you to legally distribute it, but others don't believe that's the case.


So in other words, if your program communicates via standard GTP and can 
use any GTP front-end, then you're free to distribute it with GoGui. But 
if your program is GoGui-specific in some way, such that it can't be used 
with any program except for GoGui, you're in a murky legal area.

 	~ Ross