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Releasing BB_Sudoku

 
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briturner

Joined: 14 Oct 2008
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PostPosted: Sun Oct 04, 2009 6:42 pm    Post subject: Releasing BB_Sudoku Reply with quote

Greetings,

I have received a few emails asking about releasing my BB_Sudoku code under some open license. My intentions have always been for people to be able to use the solver and be able to modify it for their own use. My only reservation is that I did not want people to just take my work and use it for commercial reasons.

I am currently investigating the various licenses that will allow this, and was wondering if anyone has opinions (either for or against any particular license).

Once I pick one, then I will re-release BB_Sudoku 0.6 as 0.65. At this point, v0.7 and other improvements I made are not ready to be released, so I will be holding those back still.

Thanks,
Brian
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m_b_metcalf

Joined: 13 Mar 2006
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PostPosted: Mon Oct 05, 2009 4:54 am    Post subject: Reply with quote

Why not keep life simple? Can't you just add a comment to your code along the lines of:
Quote:

! (c) Copyright Brian Turner, 2009. This file may be
! freely used and copied for educational purposes provided this notice
! remains attached.

The liklihood of it being exploited commercially is surely close to nil?

Regards,

Mike Metcalf
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lkSudoku

Joined: 16 May 2009
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PostPosted: Mon Oct 05, 2009 10:28 am    Post subject: Reply with quote

This seems like a GPL license type (GNU GENERAL PUBLIC LICENSE)

I came across some GPL code before, and from what I recall, GPL license allows people to read and modify the code, as long as they keep it under GPL license, and do not charge for their code which used the GPL protected code
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gsf

Joined: 18 Aug 2005
Posts: 408
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Location: NJ USA

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PostPosted: Tue Oct 06, 2009 1:50 am    Post subject: Reply with quote

lkSudoku wrote:
This seems like a GPL license type (GNU GENERAL PUBLIC LICENSE)

I came across some GPL code before, and from what I recall, GPL license allows people to read and modify the code, as long as they keep it under GPL license, and do not charge for their code which used the GPL protected code

GPL + GPL is fine
but problems arise when non-GPL code embeds GPL code,
even if the non-GPL code is covered by an open source license
BB_Sudoku is a prime candidate for embedding
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PIsaacson

Joined: 17 Jan 2006
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PostPosted: Tue Oct 06, 2009 8:09 pm    Post subject: Reply with quote

Brian,

There are several misconceptions in the above comments regarding GPL, so I strongly advise you to carefully read all of the documentation on http://www.gnu.org/licenses/.

Choose carefully, but I highly recommend GPLv3.

Cheers,
Paul
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gsf

Joined: 18 Aug 2005
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PostPosted: Tue Oct 06, 2009 8:34 pm    Post subject: Reply with quote

PIsaacson wrote:
Brian,

There are several misconceptions in the above comments regarding GPL, so I strongly advise you to carefully read all of the documentation on http://www.gnu.org/licenses/.

Choose carefully, but I highly recommend GPLv3.

Cheers,
Paul

Richard Stallman wrote:
If you include code under this license in a larger program, the larger program must be under this license too.

this is a problem for non-GPL sw
and it could be a problem for BB_Sudoku in that making it GPL may limit the sw that can embed it

the copyleft statement is so strong that GPLv2 sw cannot embed GPLV3 sw and vice versa

if there are any misconceptions with this please point them out
I don't want to be on RMS's bad side
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PIsaacson

Joined: 17 Jan 2006
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PostPosted: Tue Oct 06, 2009 11:24 pm    Post subject: Reply with quote

Refer to http://www.fsf.org/licensing/licenses/gpl-faq.html#AllCompatibility
This matrix indicates the cross-licensing combinations for various versions of GPL and LPGL.

Regarding Richard's statement -- from the FAQ about GNU licenses:
Quote:
Is GPLv3 compatible with GPLv2?

No. Some of the requirements in GPLv3, such as the requirement to provide Installation Information, do not exist in GPLv2. As a result, the licenses are not compatible: if you tried to combine code released under both these licenses, you would violate section 6 of GPLv2.

However, if code is released under GPL “version 2 or later,” that is compatible with GPLv3 because GPLv3 is one of the options it permits.

You have a GPL'ed program that I'd like to link with my code to build a proprietary program. Does the fact that I link with your program mean I have to GPL my program?

Not exactly. It means you must release your program under a license compatible with the GPL (more precisely, compatible with one or more GPL versions accepted by all the rest of the code in the combination that you link). The combination itself is then available under those GPL versions.

And from Richard Stallman himself:
Quote:
Why you shouldn't use the Library GPL for your next library

The GNU Project has two principal licenses to use for libraries. One is the GNU Lesser GPL; the other is the ordinary GNU GPL. The choice of license makes a big difference: using the Lesser GPL permits use of the library in proprietary programs; using the ordinary GPL for a library makes it available only for free programs.

I stand by my statement that there are misconceptions regarding the GNU licenses. Your quote from Richard Stallman (are you sure of the source?) is not at all factual if the included code is LGPL'ed. Even if it is GPL'ed, the larger program's licensing does not have to be under an identical GNU license, it only has to be under one that is conforming. That quote must have been taken out of context since I'm sure Richard Stallman knows every single detail of the various GNU licenses.

Cheers,
Paul

P.S. Okay - I found the page containing your excerpt from Richard Stallman's "Why Upgrade to GPLv3", but you omitted the final conclusion:
Quote:
One way to do this is to release a program under “GPL version 3 or any later version”.

Regarding future compatibility.
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gsf

Joined: 18 Aug 2005
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PostPosted: Wed Oct 07, 2009 2:37 am    Post subject: Reply with quote

PIsaacson wrote:
P.S. Okay - I found the page containing your excerpt from Richard Stallman's "Why Upgrade to GPLv3", but you omitted the final conclusion:
Quote:
One way to do this is to release a program under “GPL version 3 or any later version”.

I didn't need to add the conclusion, because all GPL solutions/conclusions lead to GPL

a non-GPL program cannot embed a GPL program

if BB_Sudoku were GPL'd then I would not be able to embed it in my solver which is CPL'd
(BB_Sudoku as a ~25% faster replacement of the sudocoo based quick verifier)
nor could any other person embed it in their non-GPL solver

Stallman's conclusion would be for me to GPL my solver, but that is not possible

via pm I recommended one of the BSD source licenses
which do not have the embedding problem and
which do provide similar protections for the owner of the sw
(it leaves out the protections for the GPL)

I'm not against GPL in general, especially for standalone apps
but BB_Sudoku has applications for embedding (just look at what spurred this on the Player's forum)
and GPL will limit those applications
e.g., if dukosu's suex* are not GPL'd then they cannot embed a GPL'd BB_Sudoku
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PIsaacson

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PostPosted: Wed Oct 07, 2009 4:00 am    Post subject: Reply with quote

Glen,

I'm unfamiliar with the BSD source licensing, but I would certainly consider LGPL as a viable solution to accomodate what I think you want: The ability to have various non-GPL'ed sources use the bb_solver code. But, it is ultimately up to Brian to decide the conditions he wishes to impose.

I would certainly recommend releasing the Solver function as a library regardless of how it is licensed. I can conceive of no purpose or advantage for directly copying or including the source in a program unless you believe that the Solve function can somehow benefit from being inline?

I would like to avoid misleading or trying to influence Brian in his decision. I believe it is important to present accurate information regarding the options available from GNU, hence my constant message to read the actual pages from the GNU web site instead of listening to opinions based on partial/incomplete knowledge (including myself...).

Cheers,
Paul
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gsf

Joined: 18 Aug 2005
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PostPosted: Wed Oct 07, 2009 4:32 am    Post subject: Reply with quote

PIsaacson wrote:
I can conceive of no purpose or advantage for directly copying or including the source in a program unless you believe that the Solve function can somehow benefit from being inline?

my embed references were related to linking and packaging, not #include
but { linking packaging #include'ing } between GPL and non-GPL are not allowed

thanks for pointing out the LGPL
I believe that would work for the player's forum request and use by other solvers
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