diff options
Diffstat (limited to 'module/srfi/srfi-41/util.scm')
| -rw-r--r-- | module/srfi/srfi-41/util.scm | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/module/srfi/srfi-41/util.scm b/module/srfi/srfi-41/util.scm index 050e1d2e..be363146 100644 --- a/module/srfi/srfi-41/util.scm +++ b/module/srfi/srfi-41/util.scm @@ -24,11 +24,19 @@ (define-public (stream-insert < item s) (interleave-streams < (list (stream item) s))) -(define-public (filter-sorted-stream proc stream) +;; Requires that stream is a total order in regards to what we filter +;; on. From there it knows that once it has found the first element +;; that satisfies our predicate all remaining elements satisfying pred +;; will be in direct succession. +(define-public (filter-sorted-stream pred stream) (stream-take-while - proc (stream-drop-while - (negate proc) stream))) + pred (stream-drop-while + (negate pred) stream))) + +;; Simmilar to the regular @code{filter-sorted-stream}, but once an +;; element satisfies @code{keep-remaning?} then the remaining tail +;; of the stream is all assumed to be good. (define-public (filter-sorted-stream* pred? keep-remaining? stream) (cond [(stream-null? stream) stream-null] [(keep-remaining? (stream-car stream)) stream] |