LuaEdit

Official site

• http://lua.org/

Lua for JavaScript programmers

This is a great resource for people coming to Lua from JavaScript. Much will be familiar:

• Functions (including anonymous functions) as first-class values.
• Closures.
• Only one real data structure, the "table" (analogous to a JavaScript object), which stands in for arrays too.
• Single and double quoted strings.

Gotchas

• "Arrays" use 1-based indexing.
• Method dispatch can be done via two operators (. for normal dispatch, and : which transparently passes the initial "self" parameter when working in Object-oriented style).
• No regular expressions; just an "pattern" facility that will seem odd to people coming from Perl-compatible regular expressions.
• Recursive functions in Lua need some care.

Other differences

• Tiny language surface area (eg. no ternaries, for example).