diff options
Diffstat (limited to 'fibers/deque.scm')
| -rw-r--r-- | fibers/deque.scm | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/fibers/deque.scm b/fibers/deque.scm index 6a41583..d427729 100644 --- a/fibers/deque.scm +++ b/fibers/deque.scm @@ -1,6 +1,7 @@ ;; Double-ended queue ;;;; Copyright (C) 2016 Andy Wingo <wingo@pobox.com> +;;;; Copyright (C) 2017 Christopher Allan Webber <cwebber@dustycloud.org> ;;;; ;;;; This library is free software; you can redistribute it and/or ;;;; modify it under the terms of the GNU Lesser General Public @@ -27,10 +28,12 @@ dequeue dequeue-all dequeue-match + dequeue-filter undequeue dequeue! dequeue-all! - enqueue!)) + enqueue! + dequeue-filter!)) ;; A functional double-ended queue ("deque") has a head and a tail, ;; which are both lists. The head is in FIFO order and the tail is in @@ -82,6 +85,12 @@ ((head . tail) (make-deque (cons item head) tail)))) +(define (dequeue-filter dq pred) + (match dq + ((head . tail) + (cons (filter pred head) + (filter pred tail))))) + (define-inlinable (update! box f) (let spin ((x (atomic-box-ref box))) (call-with-values (lambda () (f x)) @@ -110,3 +119,8 @@ (update! dqbox (lambda (dq) (values (enqueue dq item) #f)))) + +(define (dequeue-filter! dqbox pred) + (update! dqbox (lambda (dq) + (values (dequeue-filter dq pred) + #f)))) |