W3cubDocs

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.
• Generic Functions:		Polymorphism, Emacs-style.
• Function Cells:		Accessing or setting the function definition of a symbol.
• Closures:		Functions that enclose a lexical environment.
• Advising Functions:		Adding to the definition of a function.
• Obsolete Functions:		Declaring functions obsolete.
• Inline Functions:		Functions that the compiler will expand inline.
• Declare Form:		Adding additional information about a function.
• Declaring Functions:		Telling the compiler that a function is defined.
• Function Safety:		Determining whether a function is safe to call.
• Related Topics:		Cross-references to specific Lisp primitives that have a special bearing on how functions work.