
2 Syntax 2.4 Standard Macro Characters 2.4.4 Semicolon 2.4.4.2 Notes about Style for Semicolon
2.4.4.2.5 Examples of Style for Semicolon
;;;; Math Utilities
;;; FIB computes the the Fibonacci function in the traditional
;;; recursive way.
(defun fib (n)
(checktype n integer)
;; At this point we're sure we have an integer argument.
;; Now we can get down to some serious computation.
(cond ((< n 0)
;; Hey, this is just supposed to be a simple example.
;; Did you really expect me to handle the general case?
(error "FIB got ~D as an argument." n))
((< n 2) n) ;fib[0]=0 and fib[1]=1
;; The cheap cases didn't work.
;; Nothing more to do but recurse.
(t (+ (fib ( n 1)) ;The traditional formula
(fib ( n 2)))))) ; is fib[n1]+fib[n2].
