From cdd64714ad68980aaaa53bca0864d239cc2825ab Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= Date: Thu, 30 Jul 2020 13:28:35 +0200 Subject: Add stream-paginate. --- module/srfi/srfi-41/util.scm | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'module') diff --git a/module/srfi/srfi-41/util.scm b/module/srfi/srfi-41/util.scm index 2da2b479..472170d7 100644 --- a/module/srfi/srfi-41/util.scm +++ b/module/srfi/srfi-41/util.scm @@ -86,6 +86,22 @@ (stream-map cadr (stream-filter car strm)) (stream-map cadr (stream-remove car strm))))) +(define-public (stream-split idx stream) + (stream-cons (stream-take idx stream) + (stream-drop idx stream))) + +(define-stream (stream-paginate% stream page-size) + (stream-match (stream-split page-size stream) + ((page . rest) + (if (stream-null? page) + stream-null + (stream-cons + page + (stream-paginate rest page-size)))))) + +(define*-public (stream-paginate stream optional: (page-size 10)) + (stream-paginate% stream page-size)) + ;; Evaluates @var{body} in a context where most list fundamentals are ;; replaced by stream alternatives. ;; commented defifinitions are items which could be included, but for -- cgit v1.2.3