Micheal,
Keep in mind that the author of the package can give you a copy under any conditions
that they choose, they are not bound by the GPL. Simply send you code from their own
source which is "upstream" of the GPL copy. (The copy out on CRAN propogates strictly via
GPL however). You coul
As usual: For legal advice, get a lawyer... However, yes, the GPL quite
expressedly allows licencees to distribute modified versions, provided that the
modified source code is made available and is redistributable under the GPL.
It's common courtesy and possibly also required by law (the GPL it
There is a CRAN package licensed just as "GPL", say, XX, I want to use
in a book.
But I've needed to modify the package to make it do what I need for
expository purposes.
The package author(s) are amenable to my modifications, but probably
unlikely to
incorporate them into the CRAN version any
