I don't understand this. Why can't the mpl license simply
> say that it applies to all components that do not cite other
> licenses, and then leave the reference to the original
> license in any code such as GTS which has another license?
> This is not a plea for or against GTS or any other
> particular package, but rather an expression of puzzlement
> and frustration that we seem to be finding free software
> licenses limiting instead of liberating.
In my understanding, code which imports GPL'd code is obligated to
abide by the GPL restrictions itself if you want to distribute it,
specifically the copyleft part that says derived works must be open
source and distributed under the GPL. So if mpl imports a GPL module,
mpl, then any code which is for distribution that imports matplotlib
is required to be distributed under the terms of the GPL. This is
clearly unacceptable to someone who wants to distribute products that
use mpl under a proprietary license. The LGPL was introduced to solve
this problem, and it basically says that you can import it and use it
but if you change the LGPL library the library changes must be
distributed under the LGPL. I don't find it particularly
objectionable to use code which has an LGPL license, but given an
alternative, would rather have a BSD type license which is
"unencumbered".
Basically, the GPL is not particularly liberating, since it makes
strong statements about what you can do with code that uses GPL code.
JDH