Simplified Common Lisp reference

Symbol class: Mathematics, Arithmetics, Logic and Comparisons

Syntax:

Symbol type: macro

orforms^{(zero or more)} => value

Argument description:

forms

forms which value is considered

OR macro computes logical "or" function. Forms evaluation starts from left. Value from the first form that decides result is returned so forms at end of argument list may not evaluated.

(or t t t nil t) => T
(or nil nil nil) => NIL
(or) => NIL

(or (progn (write "SEEN") 123) (progn (write "UNSEEN") t)) => "SEEN" 123
(or 4 5 6) => 4

Function index Full documentation for or (HyperSpec)