empty-deque.scm (306B)
1 (define-library (sicp solutions chapter-3 exercise-23-stuff empty-deque) 2 (import (scheme base)) 3 4 (import (sicp solutions chapter-3 exercise-23-stuff front-ptr)) 5 6 (export empty-deque?) 7 8 (begin 9 (define (empty-deque? deque) 10 "Returns #t if empty, else #f." 11 (null? (front-ptr deque)))))