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;
; CSCI-4150 Introduction to Artificial Intelligence, Fall 2002
; Assignment 1 support code, Version 1.1
;
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; Definitions for problems 4 and 5
;
(define colors '(mauve chartreuse azure ochre))
(define numbers '(1 2))
(define nested-list '(((3))))
(define four 4)


; As mentioned in class today, MIT Scheme does not define "rest".
; I've defined it here because I use it in the "add-up-days" procedure
; below.
; 
(define rest cdr)

; You may find it useful to have this variable
; 
(define months '(jan feb mar apr may jun jul aug sep oct nov dec))

; (add-up-days months)
;
; This procedure depends on your "days-in-month" procedure.  If you
; have defined that procedure, this will take a list of months
; (abbreviated as 3 letter symbols) and add up the days in each month
; on the list.  (If a month is listed twice, it will be counted twice.
;
; We haven't yet covered recursive procedures in Scheme, so that's why
; I didn't assign this as another problem.  However, you should be
; able to understand how it works.
; 
(define (add-up-days months)
  (if (null? months)
      0
      (+ (days-in-month (first months))
	 (add-up-days (rest months)))))