GPL license question

[Ferdy]

I have created different pgn tools and sometimes these were distributed to other interested people.

Some of these tools uses the python-chess modules. Note that python-chess is under GPL3 license.

https://pypi.python.org/pypi/python-chess

Basically I install python and python-chess in my windows OS PC. I can then create scripts using python-chess by adding it at the top of the script,

Code: Select all

import chess
from chess import pgn
from chess import polyglot

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

Generally I don't like adding licenses to these little pgn tools.

[Evert]

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

You don't need to include the source to python-chess.

That you use a library that is under GPL, your scripts must also be released under the GPL (or a compatible licence). So yes, you probably should include the licence text/description.

[hgm]

This is why libraries usually come with the LGPL, so you can also use them with non-free programs.

[mar]

This is why libraries usually come with the LGPL, so you can also use them with non-free programs.

Yes that's why it's a bad idea to use GPL for libraries.
Even LGPL is weird as it only allows "non-free" programs to link dynamically.

I've seen a C++ template-only library under LGPL, of course you can't quite link dynamically when the library code is instantiated in your binary.

It seems to me that people should think twice before choosing a license.
The myth that open source = GPL still prevails it seems (unfortunately).
GPL is not free at all, it's a virus poisoning everything around.

[syzygy]

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

It seems the exe file will include code released under GPLv3, so you can't distribute it unless under GPLv3.

[jdart]

I agree. This is why my engine is under the MIT license.

--Jon

[Ferdy]

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

You don't need to include the source to python-chess.

That you use a library that is under GPL, your scripts must also be released under the GPL (or a compatible licence). So yes, you probably should include the licence text/description.

Thanks, I thought that releasing the source is enough. So yes I will add a license to it.

[Ferdy]

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

It seems the exe file will include code released under GPLv3, so you can't distribute it unless under GPLv3.

Thanks, I was looking for a compatible license, so now I am forced to use GPLv3 because of the creation and distribution of an exe file, all right I will do that.

[lucasart]

I have created different pgn tools and sometimes these were distributed to other interested people.

Some of these tools uses the python-chess modules. Note that python-chess is under GPL3 license.

https://pypi.python.org/pypi/python-chess

Basically I install python and python-chess in my windows OS PC. I can then create scripts using python-chess by adding it at the top of the script,

Code: Select all

import chess
from chess import pgn
from chess import polyglot

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

Generally I don't like adding licenses to these little pgn tools.

So long as you don't include python-chess with your program, you don't need a GPL.
* If you distribute your program as Python source only, and don't include python-chess sources with it, you are free to choose whatever license you want (even no license)
* If you distribute your program as Python source only, and you include python-chess sources with it, you must use the same GPL v3.
* If you distribute your program as a compiled executable, the python-chess source code is effectively combined with it, so you must use the same GPL v3.

[Ferdy]

I have created different pgn tools and sometimes these were distributed to other interested people.

Some of these tools uses the python-chess modules. Note that python-chess is under GPL3 license.

https://pypi.python.org/pypi/python-chess

Basically I install python and python-chess in my windows OS PC. I can then create scripts using python-chess by adding it at the top of the script,

Code: Select all

import chess
from chess import pgn
from chess import polyglot

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

Generally I don't like adding licenses to these little pgn tools.

So long as you don't include python-chess with your program, you don't need a GPL.
* If you distribute your program as Python source only, and don't include python-chess sources with it, you are free to choose whatever license you want (even no license)
* If you distribute your program as Python source only, and you include python-chess sources with it, you must use the same GPL v3.
* If you distribute your program as a compiled executable, the python-chess source code is effectively combined with it, so you must use the same GPL v3.

Thanks for the input.
Let me clarify on the first point.

Code: Select all

* If you distribute your program as Python source only, and don't include python-chess sources with it, you are free to choose whatever license you want (even no license)

So if I will just use python-chess modules in my code via

Code: Select all

import chess 
from chess import pgn 
from chess import polyglot

I am not required to add a license to my code?