yep this is a good point. But indeed I don't like Lua nor Tcl too much for this task. I would simply love to have an easy to embed Javascript implementation, but that does not exist.
If nothing will change under the sun I think I'll use Lua even if I don't like the language too much, but sounds like the sanest thing to do.
At a language design level, what in Javascript do you prefer to Lua? I know Javascript has more familiarity (no doubt due to this "web" thing I keep hearing so much about), but Lua seems to me like a far cleaner iteration of the same kind of language. Circumstance froze Javascript's design before it could have some major issues worked out, while Lua was able to develop more organically. They have a lot in common, though, particularly what Crockford calls JS's "good parts".
If nothing will change under the sun I think I'll use Lua even if I don't like the language too much, but sounds like the sanest thing to do.