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.