1. Lua Matthew Spain | Kerry Zhao

2. Agenda Overview of Lua Language Details Application Areas Demo Conclusion

3. Overview

4. History Made by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, and Waldemar Celes in 1993 Members of Tecgraf, PUC-Rio in Brazil Brazil had trade barriers making it hard to buy software from abroad

5. Release Timeline Jul 1993 - Lua 1.0 Jul 1994 - Lua 1.1 (first public release), paper Feb 1995 - Lua 2.1 (first free commercial release) Nov 2000 - Lua 4.0, no built-in functions Apr 2003 - Lua 5.0, multithreading, full lexical scoping Dec 2011 - Lua 5.2, current version

6. Language Influences Replaces o DEL (data-entry language) o SOL (simple object language) Scheme Modula

7. Resources www.lua.org www.lua-users.org code.google.com/p/luaforwindows luadist.org Plugins for most popular IDEs

8. Language Details

9. Function High-level scripting language Lightweight - interpreter about 180k Embedded language - C API

10. Execution Interpreter compiles to bytecode for Lua VM Very fast, usually compiled at run-time Programs can be compiled in advance to skip overhead Portable, builds on anything with a C compiler

11. Paradigms Multi-paradigm Imperative Functional Not object-oriented, but object-like constructs can be made using tables and metatables

12. Lexical/Syntactical Fun

13. Reserved Keywords and break do else elseif end false for function goto if in local nil not or repeat return then true until while

14. Types nil boolean numbers strings tables functions userdata threads

15. Control Flow if...then…else…elseif…end for...do...end while…do...end repeat...until

16. Assignment “multiple” assignment o a, b, c = “this is multiple assignment”, “yep”  i.e. a = “this is multiple assignment”, b = “yep”, c = nil o a, b = b, a  a and b have swapped values o a = a or b  if not a, a = b

17. Tables EVERYTHING IS A TABLE

18. Typing and scope Strongly typed Dynamic typing local keyword specifies non-globals Symbol table easily accessible

19. Special features Metatables Closures Special allowance for object oriented programmers

20. Metatables None by default, added with setmetatable Metamethods include: o add o sub o mul o div o mod o pow o unm o concat o len o eq o lt o le o index o newindex o call

21. Closures a function inside of a function inner function has access to local variables of the outside function

22. Object-oriented Features No classes, only prototypes Syntactic sugar for methods: function table.func(self, args) can be written as table:func(args)

23. Application Areas

24. GAMING Notables include World of Warcraft, FarCry, the CryENGINE2, Garry’s Mod, Angry Birds

25. Application Areas Cont’d IDE’s Operating Systems Plain Text Editors Robotics

26. Demo

27. Conclusion

28. References The Evolution of Lua Programming in Lua, first Edition