Re: Light Userdata Question (Lua5)

[Peter Shook <pshook@...>]

Michael T. Richter wrote:
> When would I want to use light userdatas instead of full-fledged ones?

The classic example is when you want store a lua value in a C structure, 
 but then you realize you can't because you can only store lua values 
in the registry, the globals, upvalues, or a subtable these.

So what you do is make a lookup table.  You put a regular lua table 
someplace that you have easy access to from C, such an upvalue or the 
lua registry.  Use a lightuserdata of a pointer to your structure as a 
key to the lua value you want to associate with that pointer.

Then in your C code wherever you have just the pointer, you can get the 
lua value from the lookup table.

- Peter Shook