; !!!
; .title SchemeDoc Demo 
; .author Kurt Normark
; .affiliation Aalborg University, Denmark
; This is a brief example of a Scheme program with SchemeDoc comments, 
; using the documentation mark style.

; This comment is not extracted.

; !! Factorials. 
; .section-id fac-stuff
; This section demonstrates a plain function.

;! The factorial function. Also known as n!
; .parameter n An integer
; .pre-condition n >= 0
; .returns n * (n-1) * ... * 1
(define (fac n)
 (if (= n 0) 1 (* n (fac (- n 1)))))

; !! List selection functions.
; .section-id list-stuff
; This section demonstrates two aliased functions.

;! An alias of car. 
; .returns The first component of a cons cell
; .form (head pair)
; .parameter pair A cons cell
(define head car)

;! An alias of cdr.
; .returns The second component of a cons cell
; .form (tail pair)
; .parameter pair A cons cell
(define tail cdr)