I'm writing a little embedded language for another project. While game development was not its original intent, it's starting to look like a good fit, and I figure I'll develop it in that vein at some point.

Without revealing any details (to avoid bias), I'm curious to know:

What features do you love in a scripting language for game development?

If you've used Lua, Python, or another embedded language such as Tcl or Guile as your primary scripting language in a game project, what aspects did you find the most useful?

• Language features (lambdas, classes, parallelism)

• Implementation features (performance optimisations, JIT, hardware acceleration)

• Integration features (C, C++, or .NET bindings)

• Or something entirely different?