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Re: GPLv3 comedy unfolding -- "file-level copylefts" and the GPL "will a

From: Alexander Terekhov
Subject: Re: GPLv3 comedy unfolding -- "file-level copylefts" and the GPL "will always be incompatible". And TeX...
Date: Mon, 27 Nov 2006 14:40:35 +0100

And then are licences that are file-level copylefts. The Mozilla Public
License was the first of these. File-level copylefts say "If you modify
the files of this program, the modified versions of those same files
must be under this same licence". Now, that's not as strong as the GPL.
The GPL says if you modify the program, you're whole modified program
must be under the GPL. Those file-level copylefts, or we might call them
weak copylefts, permit the additional of seperate files which are
non-free. They don't really achieve the goal of copyleft, but because
they made this requirement about the file, it's imposssible to relicense
that file under the GPL. So the GPL will always be incompatible with
those file-level copyleft licences.

Then there's the bizarre licence of TeX, which is incompatible with


The licence of TeX says "You can't modify this file, but you can
distribute it with a change file" and then when TeX is built, it's built
by patching the standard TeX source code using the change file. So, in
effect, you can distribute any modified version in that way, that's how
I convinced myself in 1984 that that was a free software licence. But if
you have two programs under the TeX licence, you can't merge them
because each one says: anything that contains this can only be
distributed as a changefile from this. So you have two things tugging at
each other, each one insisting on being the base, the TeX licence is
incompatible with itself, but it's a free software licence. 

The fellow should really go clinic...


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