[glob2-devel] Glob2 and Lua

[Stéphane Magnenat]

Hello,

I have had a look at the source code of Lua today, and it seems the 
easiest scripting system I have seen to date to embed into Glob2. In 
particular:
- It is easy to call co-routines from the host side, so that would fit 
very well our use case for scripting units, buildings and the map.
- Although Lua 5.2 uses double as numbers by default, we can compile Lua 
to use integers for numbers (providing a small rewrite of the math library).
- It is easy to remove some default libraries, so we can sandbox Lua 
inside Glob2 (and use things like the glob2 virtual file system for IO 
if we want, etc.)
- We can serialize the entire lua_State* using the ERIS distribution of 
Lua [1].

With that in mind, we can imagine an architecture in which every unit, 
building and map has a Lua_state* (i.e. a full Lua VM) and a co-routine 
handling its behaviour. These would be loaded from a Lua source code 
file, so they would be very easy to change without having to know about 
(or recompile) the core C++ engine. In addition, it would force us to 
define a clean (and documented) interface about what is provided to the 
behaviour script. This will typically be a set of values and functions.

What do you think?

cheers,

Stéphane

[1] https://github.com/fnuecke/eris

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