17.2 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 SXEmacs 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.