= Lua =


Lua is an open source scripting language whose main purpose is being embedded in C applications.  More can be learned by viewing their website at http://www.lua.org .
= Using Lua in RTEMS =

The Lua library will be included in the RTEMS distribution shortly.  Until then, you can find them at http://www.coderedonly.com/GSOC/lua/index.html
= Calling Lua Functions in C =

This operates exactly as it would in the host operating system.
<tt>
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        //This is the reference to the lua interpreter
        lua_State* L;
        
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          L = lua_open();
          luaL_openlibs(L);
          
          //Test of basic lua functionality
          lua_getglobal(L, "print");
          lua_pushstring(L, "Hello, Lua!");
          lua_call(L, 1, 0);
          lua_close(L);
       }
</tt>= Spawning a Lua Shell =

<tt>_Lua_Main(int argc, char** argv)</tt> is a standard <tt>C</tt> main function.  Lua spawns a shell whenever 
it is called without a script as an argument.  Therefore, the end user can spawn a lua shell by modifying the
code below:
<tt>
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        	    
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          char** program = calloc (2, sizeof(char*));
          
          //program[0] is the string name of the executing executable.
          program[0] = "''program.exe''";
          
          _Lua_main(1, program);
        }
</tt>
= Executing a Standalone Lua Script =

Since <tt>_Lua_Main(int argc, char** argv)</tt> is a standard <tt>C</tt> main function, executing lua scripts are
as simple as notifying the interpreter where the file is located.

''Note:'' This currently has only been tested with the [wiki:File_Systems#IMFS_File_System_  IMFS] in RTEMS.  Technically speaking, it should work
agnostic to the underlying filesystem.

<tt>
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        	    
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          char** program = calloc (2, sizeof(char*));
        
          //program[0] is the string name of the executing executable.
          program[0] = "program.exe";
          
          //program[1] is the path to the lua script to execute
          program[1] = "lua_script.lua";
          
          _Lua_main(2, program);
        }
</tt>