Packaging fparser with Cython redux

[Kurt Smith]

Pearu,

Here's an excerpt from an email discussion at the beginning of the summer:

------------------------------------------------------------------------------------------------------
> Kurt:
>> I see a few options:
>>
>> 1) Cython uses fparser as-is, fparser is strictly a part of G3 f2py
>> but is included inside the Cython distribution and is updated when
>> fparser is updated. (similar to how f2py is currently distributed
>> with numpy.) The cython backend is contained within Cython itself and
>> is packaged with it. Cython maintains the cython backend to f2py.
>> The summer project would possibly include reviewable patches to
>> fparser for improvement, all the while remaining a standalone project.
>>
>> 1b) same as above, but fparser is not packaged with Cython, and Cython
>> has an external fparser dependency for fortran support.
>>
>> 2) The cython backend is part of G3 f2py. Cython has very little
>> explicit fortran support.
>> I think the best option would be (1), assuming licensing issues are
>> compatible, and you are okay with it.
> I think (1) as well.
>
> On the question on whether Cython also distribute fparser or whether
> users have to retrieve it seperately; I think we can take that after
> summer, and it belongs partly on the Cython mailing list. Though because
> Cython aims for CPython core inclusion it might end up at 1b), so that
> users have to retrieve fparser as a seperate dependency.
>

I think for 1b) fparser needs to be stable so that its different
versions would not break Cython because of the dependency.
An option, that I have been using in other project, is to copy
a stable version fparser to Cython as a subpackage and update it
whenever a new and needed feature is implemented in fparser.
Otherwise, 1) sounds good to me too.
-------------------------------------------------------------------------------------------------

(the last paragraph is from Pearu).

I checked on the Cython mailing list, and there is tentative agreement
that packaging fparser with Cython would be a good thing (haven't
heard from all core devs yet -- perhaps they're away for a while or
they don't have a strong opinion on the matter). So I'm checking here
again to see about having Cython distribute fparser with it.

First, I presume after the email discussion above that you're fine
with distributing fparser with Cython.

Second, licensing issues -- I have no expertise here, so please let me
know if there is any licensing issues that would make inclusion
impossible. Cython is under the Apache license currently; how are G3
f2py & fparser licensed? Any incompatibilities?

Third, creating versioned branches for fparser & stabilizing the codebase:

I have yet to thoroughly test fparser 'in the wild,' each of my
testcases up until now are directed at one or two things. This will
change soon, and I'll be trying to stabilize fparser for use with
real-world code. Once things stabilize, we can talk about versioning
and branching the repo.

Thanks for making fparser available, and for allowing us access to the
codebase. It's been a tremendous help!

Kurt

[Dag Sverre Seljebotn]

Kurt wrote:
> Second, licensing issues -- I have no expertise here, so please let me
> know if there is any licensing issues that would make inclusion
> impossible. Cython is under the Apache license currently; how are G3
> f2py & fparser licensed? Any incompatibilities?

When it comes to licensing I don't believe packaging as such is the issue.
If the licenses are incompatible (like, fparser being GPL) you shouldn't
distribute fwrap in ANY form without GPLing it, packaging it with Cython
or not.

Assuming that fparser has an Apache-compatible license, I think we can
just do something like this in Cython's README:

Cython is distributed under ....

fparser (found in Tools/fwrap/fparser) is distributed under ...

IANAL,
Dag Sverre

[Pearu Peterson]

Hi,

On Aug 13, 8:22 pm, Kurt Smith <kwmsm...@gmail.com> wrote:
<snip>

> I checked on the Cython mailing list, and there is tentative agreement
> that packaging fparser with Cython would be a good thing (haven't
> heard from all core devs yet -- perhaps they're away for a while or
> they don't have a strong opinion on the matter).  So I'm checking here
> again to see about having Cython distribute fparser with it.
>
> First, I presume after the email discussion above that you're fine
> with distributing fparser with Cython.

It's ok with me.

> Second, licensing issues -- I have no expertise here, so please let me
> know if there is any licensing issues that would make inclusion
> impossible.  Cython is under the Apache license currently; how are G3
> f2py & fparser licensed?  Any incompatibilities?

f2py and fparser have BSD licenses. Cython devs
probably know better than I about any incompatibilities.

> Third, creating versioned branches for fparser & stabilizing the codebase:
>
> I have yet to thoroughly test fparser 'in the wild,' each of my
> testcases up until now are directed at one or two things.  This will
> change soon, and I'll be trying to stabilize fparser for use with
> real-world code.  Once things stabilize, we can talk about versioning
> and branching the repo.

Sounds good.

> Thanks for making fparser available, and for allowing us access to the
> codebase.  It's been a tremendous help!

Thanks for working on improving fparser!

Regards,
Pearu

[Kurt Smith]

On Thu, Aug 13, 2009 at 12:55 PM, Pearu
Peterson<pearu.p...@gmail.com> wrote:
>
> Hi,
>
> On Aug 13, 8:22 pm, Kurt Smith <kwmsm...@gmail.com> wrote:
> <snip>
>> I checked on the Cython mailing list, and there is tentative agreement
>> that packaging fparser with Cython would be a good thing (haven't
>> heard from all core devs yet -- perhaps they're away for a while or
>> they don't have a strong opinion on the matter).  So I'm checking here
>> again to see about having Cython distribute fparser with it.
>>
>> First, I presume after the email discussion above that you're fine
>> with distributing fparser with Cython.
>
> It's ok with me.

Great! Thank you.

>
>> Second, licensing issues -- I have no expertise here, so please let me
>> know if there is any licensing issues that would make inclusion
>> impossible.  Cython is under the Apache license currently; how are G3
>> f2py & fparser licensed?  Any incompatibilities?
>
> f2py and fparser have BSD licenses. Cython devs
> probably know better than I about any incompatibilities.

IANAL, but if this slide is in any way authoritative, then there are
no problems using/packaging BSD code in Apache-licensed code, assuming
the license versions are up-to-date:

http://www.dwheeler.com/essays/floss-license-slide.html

I'll do a bit of reading to see what requirements there are in the BSD
license for packaging. We'll give due attribution to you in the docs,
of course. Besides that I'll just be reading the BSD license and
going from there.