ifの評価と関数の評価

#!/usr/bin/env scheme

(define (log name)
	(begin
	 (display name)
	 (newline)
	 #t))

(define (f-test)
	(log "f-test"))

(define (f-then)
	(log "f-then"))

(define (f-else)
	(log "f-else"))

(define (new-if x y z)
	(cond (x y)
	      (else z)))

(display (if (f-test) (f-then) (f-else)))
(newline)
(display (new-if (f-test) (f-then) (f-else)))
(newline)