Lua License

wiki

Currently this page is a critique of the Lua license.

Here is the text (or see [original]):

Copyright © 1994-2000 TeCGraf, PUC-Rio. All rights reserved.

Permission is hereby granted, without written agreement and without license or royalty fees, to use, copy, modify, translate, and distribute this software and its documentation (hereby called the "package") for any purpose, including commercial applications, subject to the following conditions:

• The above copyright notice and this permission notice shall appear in all copies or substantial portions of this package.
• The origin of this package must not be misrepresented; you must not claim that you wrote the original package. If you use this package in a product, an acknowledgment in the product documentation would be greatly appreciated (but it is not required).
• Altered source versions must be plainly marked as such, and must not be misrepresented as being the original package.

The authors specifically disclaim any warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The package provided hereunder is on an "as is" basis, and the authors have no obligation to provide maintenance, support, updates, enhancements, or modifications. In no event shall TeCGraf, PUC-Rio, or the authors be held liable to any party for direct, indirect, special, incidental, or consequential damages arising out of the use of this package and its documentation.

The Lua language and this implementation have been entirely designed and written by Waldemar Celes, Roberto Ierusalimschy and Luiz Henrique de Figueiredo at TeCGraf, PUC-Rio in Brazil.

This implementation contains no third-party code.

This license seems similar to the BSD license [2].

While such a proprietary license is convenient for Tecgraf and PUC-Rio lawyers, it is not convenient for the free software community. The open source and free software communities need software with well-known licenses so that when the inevitable questions arise like "can I use Lua in my GPL'd software?" one need only consult readily available information about license compatibility [3].

The statements "... this implementation have been entirely designed and written by...", and "this implementation contains no third-party code," which supposedly must be included in the license of all derived works, is also a problem. Derived works obviously may include code not written by the Lua authors, or third-party code, causing these statements to be false.

Note: the copyright date should be updated :-) The "This implementation contains no third-party code." note is also annoying because it can means that Lua cannot include code submitted by other contributors. At least, not by without a full rewritting by the authors... Indeed, the two lines about the implementation should be removable or we should be able to edit them as "The original implementation...". --PhilippeLhoste

From Roberto's posting it seems that by "Lua implementation" they mean Lua itself and not the source code. Certainly "implementation" was a bad choice of words.

See Also

• OtherLicenses
• LuaList:2008-09/msg00602.html LuaList:2008-10/msg00001.html - Lua licensing thoughts