Masterminds of Programming

Chapter 7. Lua

Lua is a very small, self-contained dynamic language created by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, and Waldemar Celes in 1993. Lua’s small set of powerful features and easy-to-use C API make the language easy to embed and extend to express domain-specific concepts. Lua is prominent in the world of proprietary software, where games such as Blizzard’s World of Warcraft and Crytek GmbH’s Crysis, as well as Adobe’s Photoshop Lightroom, use it for scripting and UI work. Its predecessors are Lisp, Scheme, and perhaps AWK; it has design similarities to JavaScript, Icon, and Tcl.

The Power of Scripting

How do you define Lua?

Luiz Henrique de Figueiredo: An embeddable, lightweight, fast, powerful scripting language.

Roberto Ierusalimschy: Unfortunately, more and more people use “scripting language” as a synonym for “dynamic language.” Nowadays even Erlang or Scheme are called scripting languages. That is sad, because we lose the precision to describe a particular class of dynamic languages. Lua is a scripting language in the original meaning of the expression. A language to control other components, usually written in another language.

What should people keep in mind when designing software with Lua?

Luiz: That there probably is a Lua way of doing things. It’s not recommended to try to emulate all practices from other languages. You have to really use the features of your language, although I guess that is true for any language. In the case of Lua, those features ...