Re: [Haskell-cafe] Re: ANN: hakyll-0.1

2009/12/12 Stephen Tetley :

2009/12/12 Tom Tobin :

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1) Can the author of Y legally distribute the *source* of Y under a non-GPL license, such as the 3-clause BSD license or the MIT license?

Hello Tom

If the answer to this isn't yes, I'll buy a hat and eat it...

As source, Y (the BSD3 library) can surely be distributed as the author sees fit. The author could even distribute Y as source under a non-GPL _compatible_ license. This would hamper the utility Y, neither the author of Y nor anyone else could distribute an executable that agglomerates X and Y, but I honestly can't see how the existence of library X (GPL) can make it illegal to distribute other distinct works (my emphasis on _distinct_).

Now, author X could choose to sue author Y for copyright infringement. If such a case happened it might set the precedent for what a 'derived work' is - vis-a-vis GPL and libraries - from my cursory web searching, such a case hasn't happened. From the 'Linking and derived works' bit in the Wikipedia page, the judgement on copyright law notes "the infringing work must incorporate a portion of the copyrighted work in some form", surely the judges would have to decide whether or not calling API's and reusing datatypes is incorporation.

http://en.wikipedia.org/wiki/GNU_General_Public_License

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3) If the answer to 1 is "yes", what specifically would trigger the redistribution of a work in this scenario under the GPL? Is it the distribution of X+Y *together* (whether in source or binary form)?

Don't know.

In the case of Hakyll and other packages on Hackage, the distribution is in source form. If someone wanted to repackage the code from Hackage as a binary distro they would have different obligations.

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4) If the answer to 1 is "yes", does this mean that a "BSD-licensed" library does not necessarily mean that closed-source software can be distributed which is based upon such a library (if it so happens that the library in turn depends on a copylefted library)?

The 'closed-source' software here still depends on a 'copyleft' library - if the library is GPL then the terms of the GPL apply. Whether there is an intermediary BSD licensed library is surely immaterial.

I'd like to point out a possible situation, that makes the questions even more interesting. Say the author of Y (the BSD licensed code) is used to install its code, Y, along of its requisite X (under GPL) to customer locations. Note that Y and X are not (re)distributed in compiled form. In fact, the client could have the internal resource to install and configure Y and its requisite himself (if Y was made available to him). Is it ok in regard of the GPL ? Cheers, Thu