I'm looking for a scripting language that works on 32-bit and 64-bit machines as well as on Windows and Linux. I will be embedding it into a C++ application so I prefer it to be natively written in C++ rather than C. I also would prefer the script to have thread/asynchronous support.
So far the languages that I have looked at are GameMonkey, Lua, and V8 JavaScript Engine. V8 JavaScript has the most appeal so far. I don't really want to use GameMonkey because AFAIK it doesn't support 64-bit addressing. Lua is written in C so I would probably use the C++ wrapper, but I really don't like mixing C and C++ code.
So are there some other alternatives that I could look at?
I say Lua. It's ultraportable (It even runs under PalmOS, WindowsCE and DOS!), small (200-300k), fast and it is very easy to interface it with C/C++.
Also, Michael Pall makes amazing progress with his LUA JIT implementation. His current beta-4 supports x86 and x86_64 jitting and beats the crap out of almost every interpreter language I know: http://luajit.org/