12. Functions

A Lisp program is composed mainly of Lisp functions. This chapter explains what functions are, how they accept arguments, and how to define them.

12.1 What Is a Function?		Lisp functions vs. primitives; terminology.
12.2 Lambda Expressions		How functions are expressed as Lisp objects.
12.3 Naming a Function		A symbol can serve as the name of a function.
12.4 Defining Functions		Lisp expressions for defining functions.
12.5 Calling Functions		How to use an existing function.
12.6 Mapping Functions		Applying a function to each element of a list, etc.
12.7 Anonymous Functions		Lambda expressions are functions with no names.
12.8 Accessing Function Cell Contents		Accessing or setting the function definition of a symbol.
12.9 Inline Functions		Defining functions that the compiler will open code.
12.10 Other Topics Related to Functions		Cross-references to specific Lisp primitives that have a special bearing on how functions work.