12.2 Lambda Expressions

A function written in Lisp is a list that looks like this:

     (lambda (arg-variables...)
       [documentation-string]
       [interactive-declaration]
       body-forms...)

Such a list is called a lambda expression. In Emacs Lisp, it actually is valid as an expression—it evaluates to itself. In some other Lisp dialects, a lambda expression is not a valid expression at all. In either case, its main use is not to be evaluated as an expression, but to be called as a function.

• Lambda Components: The parts of a lambda expression.
• Simple Lambda: A simple example.
• Argument List: Details and special features of argument lists.
• Function Documentation: How to put documentation in a function.