;;; For a positive delay, returns a stream ;;; with "delay" zeros prepended. For ;;; negative delays, removes "delay" items ;;; from the input. (define (stream-delay stream delay) (cond ((= delay 0) stream) ((> delay 0) (cons-stream 0 (stream-delay stream (dec delay)))) (else (stream-delay (stream-cdr stream) (inc delay)))))