Re: Revisiting the SPDX license representation syntax

Philippe Ombredanne

On Tue, Oct 29, 2013 at 7:26 AM, Wolfgang Denk <wd@...> wrote:
In message <CAOFm3uEDjBvgyWLTsp0xMXe1vRefoMaAPEnzKhekdx6+-xVohg@...> you wrote:
Here are the basic examples updated to SPDX:
Thanks - I mostly like this, but I would like to suggest a few minor
changes to make life easier especially to developers who are used to
standard operators in programming languages:
Guten Tag Wolfgang!
and thanks for your feedback.

* mit ? gpl-2.0 : a disjunctive license choice of mit or gpl-2.0.
A choice must be made. (CHOICE, EXCLUSIVE OR, DISJUNCTION)
In C and some other programming languages, the EXCLUSIVE OR operator
is '^', so please make this "mit ^ gpl-2.0".

* gpl-2.0 ^ classpath : a license exception or supplemental terms:
here, the classpath exception to the gpl-2.0. nb: here we have a
slight change with the SPDX license list, where the exception would be
just the exception and not the whole gpl-and-classpath taken together
as one license.(EXTRA TERMS, EXCEPTION)
Please use a different operator t mark an exception, as '^' is kind of
reserved for XOR.
You are absolutely right there and being a programmer I had hesitated
a little about the implications then,
and thought that it would be OK to forego programming conventions.
Expressing disjunctions with a caret ^ makes perfect sense.
In this case, and this would be a good simplification the explicit
ampersand & or the implicit space AND separator could be used for a
license exception or supplemental terms which is really all that is
For instance:
gpl-2.0 + & classpath: I am licensed under the GPL 2.0 or any later
version with the Classpath expection
which could rephrased also as something more or less equivalent for
such as this, because the classpath exception states that it can be
(gpl-2.0 + & classpath) ^ gpl-2.0 + : you must select the GPL 2.0 or
3.0 with or without the Classpath exception

Note that FWIW this little language of mine was buried in notes I
wrote down four years ago, and has never been in use practically....
I just adapted it in this email thread to use SPDX license keys.

Philippe Ombredanne

+1 650 799 0949 | pombredanne@...
DejaCode Enterprise at
nexB Inc. at

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