The Kepler FAQ is divided into three parts:
A General FAQ for questions about the whole project, a User FAQ for questions related to Kepler use and a Dev FAQ for questions related to the development of Kepler and its modules.
What is Kepler?
Kepler is an open source platform implemented as a set of Lua components and offers the same advantages as Lua: it is simple, extremely portable, light and extensible. It is also the name of the project that is developing the Kepler platform.
Why "Kepler"?
Johannes Kepler was the astronomer that first explained that the tides are caused by the Moon. "Lua" means Moon in Portuguese, so the name "Kepler" tries to hint that some new tides may soon be caused by Lua... :o)
What is Lua?
Lua is a programming language that offers a very impressive set of features while keeping everything fast, small and portable. The Kepler Platform uses these features to offer a faster, smaller and more portable way to develop Web applications.
What is a Web application?
Web applications (also known as Web apps) are programs that are used through a Web browser. Every time you search for something with Google, read mail with Hotmail or browse Amazon you are using a Web application. Some other examples would be discussion forums, a blog or a weather site.
What is a Web development platform?
Web applications can be developed in different ways, from a hands-on approach to a very structured one. A Web development platform offers the developer a number of features that make the development of Web applications a lot easier. Instead of developing the application from scratch, the developer can benefit from the building blocks of the Web platform.
Why build/use another Web development platform?
There are a number of great Web development platforms out there but none balances power, size and flexibility quite like Kepler does. For more details check our Vision page.
Is Kepler better than PHP/Java/.Net/...?
That depends on what is your goal. Those platforms are surely good solutions for Web Development but sometimes they turn out to be too big, too rigid or just too unportable for the job. That's precisely where Kepler shines. For more details check our Vision page.
What about the licensing and pricing models?
Kepler and Lua are free software: they can be used for both academic and commercial purposes at absolutely no cost. There are no royalties or GNU-like "copyleft" restrictions. Kepler and Lua qualifies as Open Source software. Their licenses are compatible with GPL. Kepler is not in the public domain and the Kepler Project keeps its copyright. (See also: License.)
How ready to use is Kepler?
Kepler development is an ongoing process, and you can check the latest release at the Downloads page. Instructions for installation on Unix and Windows can be found at the Installation page.
You can also check the News page for the incoming releases.
Who is already using Kepler?
Kepler is already being used by various groups around the world and by PUC-Rio, Fábrica Digital on professional applications.
Is there a mailing list for Kepler?
Yes! Kepler questions can be posted on the Kepler Project Mailing List.
How can I help?
There are a lot of ways to help the project and the team.
One way is to use Kepler and provide some feedback, check the Users section for that.
If you want to follow more closely, you can join the Kepler Project Mailing List or the Kepler forums on LuaForge.
You can also help developing and debugging the existing modules, as much as helping document the platform and its modules. Please go to the Developers section for more information for that.
Another way to help would be buying something from Amazon through the PiL links on LuaForge and the Kepler sites. Doing that you'll be helping gather resources for the Kepler team.
For every product (not just PiL) bought after entering Amazon through the links we get from 2% to 5% of the product price as Amazon credits. Those credits are used to buy books for the team, so we can stay sharp and deliver the goods. :o)
For those interested in helping us this way, just remember that Amazon only considers products added to the cart after you enter Amazon through the Kepler links. Anything in the cart that was added during a different visit to the store will not count for us (though it may count for another Amazon partner).