21.2 Defining Commands

A Lisp function becomes a command when its body contains, at top level, a form that calls the special form interactive. This form does nothing when actually executed, but its presence serves as a flag to indicate that interactive calling is permitted. Its argument controls the reading of arguments for an interactive call.

• Using Interactive: General rules for interactive.
• Interactive Codes: The standard letter-codes for reading arguments in various ways.
• Interactive Examples: Examples of how to read interactive arguments.