[Rd] forking a CRAN project

[Michael Friendly]

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 time soon.

Am I allowed, under GPL, to create a new version of the package, say 
XX2, in a
public repository such as R-Forge or github?  I would, of course, 
maintain their
authorship, though perhaps take over the maintainer role.  For my 
purposes in
the book, I don't necessarily need to release my version to CRAN; just a 
public repo
a reader could download from.

-Michael

-- 
Michael Friendly     Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University      Voice: 416 736-2100 x66249 Fax: 416 736-5814
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