- (or <test> ...)syntax
The <test> expressions are evaluated from left to right, and the value of the first expression that evaluates to a true value (see the section about booleans) is returned. Any remaining expressions are not evaluated. If all expressions evaluate to false values, the value of the last expression is returned. If there are no expressions then #f is returned.
(or (= 2 2) (> 2 1)) ===> #t (or (= 2 2) (< 2 1)) ===> #t (or #f #f #f) ===> #f (or (memq 'b '(a b c)) (/ 3 0)) ===> (b c)