Refer to - http://wiki.infinitegrid.org/index.php/LuaSL_-_New_scripting_engine

LuaSL is a Lua based LSL scripting engine that will aim for LSL
compatability first, then adding Lua extensions.  It aims to replace the
woeful XEngine from OpenSim, and at a later stage, be the basis for a
client side scripting engine.

To compile this, you will need Enlightenment Foundation Libraries (EFL)
installed in either /opt/e17 or /usr.  These are typical places it get's
installed in.  You will also need flex.  The rest of the dependencies
are in the ../libraries directory, including the source code for the
version of EFL this is tested with.


Design.
-------

The basic design will be made up as I go along, but so far I have this -

An object is a file system directory, full of LSL scripts as text files,
notecards as text files, animations as BVH (or later BVJ) files, etc. 
There will be some sort of metadata in place.  This could be created by
our own OpenSim compatible cache module.

A parser parses an LSL script, validating it and reporting errors.

A preprocessor takes the result of the parse, and converts it into Lua
source.  Each LSL script becomes a Lua state.  LSL states are handled as
Lua tables, with each LSL state function being a table function in a
common metatable.  LL and OS functions are likely to be C or Lua
functions.  Careful testing should be done with LuaJIT FFI, sandboxing,
and performance testing.

The Lua source is compiled by the Lua compiler.

LuaJIT is used as the Lua compiler, library, and runtime.

Luaproc is used to start up operating system threads and hand Lua states
between them.  Luaproc messaging is also being used, but might need to
change to edje messaging.

Nails is used to pump commands in and out of the LuaSL system.  Incoming
commands invoke LSL events via the LuaSL state metatable.  LL and OS
functions that impact the world will be converted to nails commands sent
to the command pump.

Initialy, since this is the first thing being written, a nails command
pump client needs to be installed into OpenSim's C# stuff.  Though it
might be possible to talk directly to ROBUST instead.  Think I'll try
the ROBUST route, see how far I can get.  That's the general principle
applying in all of this - try to avoid C# and see how for we can get. 
lol

A watchdog thread is used to make sure no LuaSL script spends forever
processing any event.

Some form of serialization will need to be created for saving script
state during shutdowns, passing script state to other threads /
processes / computers.

There will have to be a MySQL (and maybe SQLite) client in the system,
so we can talk directly to the local sim database.  Esskyuehl may be
suitable, though it's still in the prototype stage.

Email, HTTP, and XML-RPC might need to be dealt with by us.  A ROBUST
client will be needed to.  Azy might be suitable, but it's also in
prototype.


Test harness.
-------------

I'll build a test harness.  It will be based on EFL Edje Lua, with
buttons for triggering LSL events, SL style dialogs, and other goodies.

The initial goal will be to run standard MLP scripts.  They have minimal
interface to the world, and exercise quite a bit of the rest of LSL. 
They are also quite common, and sometimes responsible for a lot of the
script running load.

Later I should add stock standard OpenCollar scripts from SL.  They are
a bitch to get working under OpenSim, so would be good compatability
tests.

Various eina logging domains will be used to handle whisper, say, shout,
etc.

Performance testing will have to be done on 5000 scripts, to see how
that compares against XEngine.