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

Stephen Tetley stephen.tetley at gmail.com
Sat Dec 12 04:41:43 EST 2009

2009/12/12 Tom Tobin <korpios at korpios.com>:

> 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.


> 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.

> 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

Best wishes


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