Robert Greayer wrote:
There's still a lot of gray area here -- the mere existence of a dependency doesn't imply that a software package is useless without the dependency, so there are many situations in which P could depend on Q and not be a derivative of Q, because the dependency can be disabled in some way and the software would still function. As an example -- pandoc can be built with or without highlighting-kate, and is useful either way. They're both GPL and by the same author, so there's no issue, but were that not the case it would seem obvious that pandoc isn't derivative of -kate, and thus could (by this reasoning) be released independently under different terms. The same may not be true of the hakyll / pandoc situation which sparked this controversy.
From what I gather, Hakyll is helper program / library for generating static websites. It uses pandoc to offer a default markdown -> html converter, which means that it's also useful without it.
Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com