gistfile1.scm

(use gauche.generator)
(use gauche.lazy)

(define-syntax chain
  (syntax-rules ()
    ((_ ls (p1 p2)) (p1 p2 ls))
    ((_ ls (p1 p2) x ...)
     (begin (chain ls (p1 p2))
            (chain ls x ...)))))

(define (tmpgen cnt)
  (generate
    (lambda (yield)
      (let loop ([i 0]) 
        (when (< i cnt)
          (print "Generate: " i)
          (yield i)
          (loop (+ i 1)))))))

(chain (generator->lseq (tmpgen 10))
       (lmap (^x (* x 2))))

(chain '(1 2 3 4 5)
       (map (^x (* x 2)))
       (map (^x (+ x 1))))
;; => (3 5 7 9 11)

(take (chain (lrange 0)
             (lmap (^x (* x 2))))
      10)
;; => (0 2 4 6 8 10 12 14 16 18)