= 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 =

For now, you can find the lua rtems files at http://gwu.webhop.net/~cssmith/GSOC/index.html
= Calling Lua Functions in C =

This operates exactly as it would in the host operating system.
{{{
        #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);
       }
}}}
= Spawning a Lua Shell =

`_Lua_Main(int argc, char** argv)` is a standard `C` 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:
{{{
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        	    
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          _Lua_spawn_shell();
        }
}}}

= Spawning a RTEMS Shell =

This creates a lua shell that allows for the execution of RTEMS commands.
{{{
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        	    
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          _Lua_spawn_RTEMS_shell();
        }
}}}

= Executing a Standalone Lua Script =

Since `_Lua_Main(int argc, char** argv)` is a standard `C` 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.

{{{
        #include <rtems/lua.h>
        #include <rtems/lualib.h>
        #include <rtems/lauxlib.h>
        	    
        rtems_task Init(
          rtems_task_argument ignored
        )
        {
          char** program_args = NULL;
          /*
             Setup arguments for the lua script, if any
          */
          _Lua_run_script("path-to-program.lua", num_arguments, program_args);
        }
}}}