eLua stands for Embedded Lua and the project aims to offer the full set of features of the Lua Programming Language to the embedded world.
eLua is not a stripped down set of Lua; much on the contrary, it strives to offer the same features as the desktop version of Lua, but complementing them with specific features for embedded use. Besides offering different flavors of the full Lua implementation (like the possiblity of choosing between an integer-only and a floating point numbers implementation), a lot of work was and will be done in the direction of making Lua more "embedded-friendly" by augmenting the core language with features that allow lower memory requirements.
Lua is the perfect example of a minimal, yet fully functional language. Although generally advertised as a "scripting language" (and used accordingly especially in the game industry), it is also fully capable of running stand-alone programs. Its limited resource requirements make it suitable to a lot of microcontroller families. The intrinsic high portability of the original Lua code (which is ANSI C and runs virtually on every platform for which an ANSI C compiler is available) combined with the highly portable software architecture of eLua allow for easy porting of the project to a large variety or architectures. The peripheral access libraries exported by eLua are also portable by design, so one could run a Lua program (without or with very few modifications) on every eLua supported platform (the project status & roadmap shows a constantly growing list of platforms on which eLua is supported). eLua inherits the minimalistic and functional design of Lua, staying in line with the well known KISS, Keep It Small and Simple philosophy.
The aim of the project is to have a fully functional Lua development environment on the microcontroller itself, without the need to install a specific development environment on the PC side. This includes the ability to both edit and debug programs directly on target. Initially, a PC will still be needed in order to edit the Lua programs for the microcontroller. But as the project evolves this requirement will be relaxed, as a basic editor (also residing on the microcontroller) will be usable with a variety of input/output devices.
We can't end this short presentation without presenting our project motto: No matter what you do with eLua, always remember to have fun with it :)
As already stated, eLua allows you to run Lua completely on the target microcontroller. A fast-growing set of complementary modules is also provided, for programming eLua's peripherals.
The following important features are ready or being implemented:
For more information about the functionality (implemented and planned) in eLua check the status page.
Porting eLua to another compatible platform should be as easy and painless as possible. Currently this is restricted to platforms for which the gcc+newlib combo is available. This restriction will disappear in the near future, as eLua will have its own libc and thus it will be available on a much broader range of MCUs.
The Lua implementation comes in two flavors: "regular Lua" (using floating point as the number type) and "integer Lua" (using integers). "Regular Lua" will be able to perform floating point operations (but will be slower because the floating point operations will be emulated in software on the MCU), while "integer Lua" will only be able to perform operations with integer numbers (but support for fixed and even floating point can be added with separate modules) and thus will be faster.
eLua has a wide and varied audience, starting from newcomers to the embedded world who want an easy and powerful environment for prototyping, rapid application development and quick production, and ranging towards highly skilled developers that want to extend their programs with the Lua library facilities and portable features.
eLua allows embedded-oriented programmers to use the simplicity and power of the Lua programming language and to hide the low-level complexities and platform/architecture-dependent features. With eLua, the programmer can focus on the actual implementation of his program, without having to worry about accessing the low-level peripheral configuration and data registers, as the platform libraries already take care of this. This increases productivity and eliminates the often frustrating task of dealing with platform-specific drivers.
The list below summarizes eLua's target audience:
eLua is a joint project of Bogdan Marinescu, a software developer from Bucharest (Romania) and Dado Sutter, head of the Led Lab at PUC-Rio University, in Rio de Janeiro (Brazil).
Its origins come from the ReVaLuaTe project also developed by Bogdan Marinescu (as a contest entry for the 2005 Renesas M16CDesign Contest), and the Volta Project, managed by Dado Sutter at PUC-Rio from 2005 to 2007.
eLua is Open Source and an always growing list of collaborators can be found in our Credits Page
| ReVaLuaTe Project | Volta Project |
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eLua authors can be contacted at:
Bogdan Marinescu: bogdan.marinescu -at- gmail.com
Dado Sutter: dadosutter -at- gmail.com
You are also welcomed to share your questions and suggestions on our Mail Discussion List
eLua is Open Source and is freely distributed under the MIT licence.
The Lua code (with all the eLua specific changes) is included in the source tree and is, of course, licensed under the same MIT license that Lua uses.
There may be other components with different licenses in eLua, see COPYING in the source distribution for details.