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.

• What Is a Function: Lisp functions vs. primitives; terminology.
• Lambda Expressions: How functions are expressed as Lisp objects.
• Function Names: A symbol can serve as the name of a function.
• Defining Functions: Lisp expressions for defining functions.
• Calling Functions: How to use an existing function.
• Mapping Functions: Applying a function to each element of a list, etc.
• Anonymous Functions: Lambda expressions are functions with no names.
• Function Cells: Accessing or setting the function definition of a symbol.
• Inline Functions: Defining functions that the compiler will open code.
• Related Topics: Cross-references to specific Lisp primitives that have a special bearing on how functions work.