Programming in Lua : p1.1

This first edition was written for Lua 5.0. While still largely relevant for later versions, there are some differences.
The fourth edition targets Lua 5.3 and is available at Amazon and other bookstores.
By buying the book, you also help to support the Lua project.

Programming in Lua

Preface

Audience

Lua users typically fall into three broad groups: those that use Lua already embedded in an application program, those that use Lua stand alone, and those that use Lua and C together.

Many people use Lua embedded in an application program, such as CGILua (for building dynamic Web pages) or LuaOrb (for accessing CORBA objects). These applications use the Lua-C API to register new functions, to create new types, and to change the behavior of some language operations, configuring Lua for their specific domains. Frequently, the users of such applications do not even know that Lua is an independent language adapted for a particular domain; for instance, CGILua users tend to think of Lua as a language specifically designed for the Web.

Lua is useful also as a stand-alone language, mainly for text-processing and one-shot little programs. For such uses, the main functionality of Lua comes from its standard libraries, which offer pattern matching and other functions for string handling. We may regard the stand-alone language as the embedding of Lua into the domain of string and (text) file manipulation.

Finally, there are those programmers that work on the other side of the bench, writing applications that use Lua as a library. Those people will program more in C than in Lua, although they need a good understanding of Lua to create interfaces that are simple, easy to use, and well integrated with the language.

This book has much to offer to all those people. The first part covers the language itself, showing how we can explore all its potential. We focus on different language constructs and use numerous examples to show how to use them for practical tasks. Some chapters in this part cover basic concepts, such as control structures. But there are also advanced (and original) topics, such as iterators and coroutines.

The second part is entirely devoted to tables, the sole data structure in Lua. Its chapters discuss data structures, persistence, packages, and object-oriented programming. There we will unveil the real power of the language.

The third part presents the standard libraries. This part is particularly useful for those that use Lua as a stand-alone language, although many other applications also incorporate all or part of the standard libraries. This part devotes one chapter to each standard library: the mathematical library, the table library, the string library, the I/O library, the operating system library, and the debug library.

Finally, the last part of the book covers the API between Lua and C, for those that use C to get the full power of Lua. This part necessarily has a flavor quite different from the rest of the book. There we will be programming in C, not in Lua; therefore, we will be wearing a different hat. For some readers, the discussion of the C API may be of marginal interest; for others, it may be the most relevant part of this book.