This first edition was written for Lua 5.0. While still largely relevant for Lua 5.1, there are some differences.
The second edition targets Lua 5.1 and is available at Amazon and as an e-book.
By buying the book, you also help to support the Lua project.

Part I. The Language Chapter 4. Statements

4 – Statements

Lua supports an almost conventional set of statements, similar to those in C or Pascal. The conventional statements include assignment, control structures, and procedure calls. Lua also supports some not so conventional statements, such as multiple assignments and local variable declarations.