embedded lua: invocation overhead?

["Gabor Szokoli" <szocske@...>]

Hi there!

We are evaluating our options for a simple embedded language for our
configuration files. Our expectations for the language itself are
light: simple assigments and arithmetic on integers and strings,
if-then-else, loops, functions.
The requirements are strict for runtime performance, especially low
invocation overhead: thousands of short scripts will get invoked every
second!
We'll be injecting different c++ object instances (of the same type)
for the scripts to manipulate.
I have seen the abundance of tutorials and documents explaining how to
do this with lua, which is great. I'll read them all if you guys can
give promising answers to these questions:
- What can we expect in such "impulse" performance?
- What are the things I can trade off for startup speed? I'm sure I
won't need a garbage collector for example, no sustained script
execution.
- Would startup time benefit from using LuaJIT Ahead of Time compilation?
- Can I make sure no script can hurt the host process?
- Can I destructively interrupt the "parse" (or whatever the
equivalent of dofile is for an in-memory bytecode-compiled script
which I am sure I can cache and reuse) function when a safety timer
expires?

Our current contenders for the role in order of preference:
Lua, "roll our own" (possibly with XIDEK), and Squirrel.
Let me know if you know of any other likely competitors :-)


Thanks for any advice:

Gabor Szokoli