Lua is a powerful, fast, lightweight, embeddable scripting language.

Lua combines simple procedural syntax with powerful data description
constructs based on associative arrays and extensible semantics. Lua is
dynamically typed, runs by interpreting bytecode for a register-based
virtual machine, and has automatic memory management with incremental
garbage collection, making it ideal for configuration, scripting, and
rapid prototyping.

This version of Lua isn't the most recent version but it's still widely
used, due to popularity of LuaJIT 2.0 which is compatible with Lua 5.1.