Up to this point in the book you've been learning about the fundamentals of Lua, occasionally using some of its library functions. In this chapter, all of Lua's standard library functions are briefly summarized to remind you of their basic usage. Practically every function has many more features than can be covered in detail within the scope of this book, and the examples that are included here are mostly contrived for brevity. (For the definitive documentation of these features, see the Lua Reference Manual.)
In this chapter, you'll find summaries of the following:
General-purpose functions in the core library
Functions that manage coroutines
Package functions that implement Lua's module system
String conversion and pattern matching functions
Functions that help with using tables as arrays
Bindings to the C runtime library's math functions
Functions for reading from and writing to files and streams
Operating system functions
Functions to help with debugging your Lua programs
An example is provided for each function or group of functions.
The core library functions reside in the global environment. They have no containing namespace table.
The following functions let you set and retrieve a function's environment—the table that Lua uses to resolve global references—and get or set the global environment of the running thread when given a stack level of 0:
getfenv(optional function or stack level): Returns the environment table ...