closures

(define marks-age 44)
(display (string-append "I can retire in " (number->string (- 67 marks-age)) " years."))
(newline)

(define (get-retirement-calculator retirement-age)
    (lambda (age) (- retirement-age age)))
(define optimistic (get-retirement-calculator 67))
(define pessimistic (get-retirement-calculator 72))
(define really-depressing (get-retirement-calculator 100))
(display (string-append "Optimistically I can retire in " (number->string (optimistic marks-age)) " years."))
(newline)
(display (string-append "Pessimistically I can retire in " (number->string (pessimistic marks-age)) " years."))
(newline)
(display (string-append "I hope it doesn't come to this... I can retire in " (number->string (really-depressing marks-age)) " years."))
(newline)