Add sequences.lib.reduce-index

2008-04-19 23:41:18 -07:00 · 2008-04-19 23:41:18 -07:00 · 6c70907354
parent c564481cc5
commit 6c70907354
1 changed files with 4 additions and 0 deletions
--- a/extra/sequences/lib/lib.factor
+++ b/extra/sequences/lib/lib.factor
@ -35,6 +35,10 @@ MACRO: firstn ( n -- )
    #! quot: ( elt index -- obj )
    prepare-index 2map ; inline

+: reduce-index ( seq identity quot -- )
+    #! quot: ( prev elt index -- next )
+    swapd each-index ; inline
+
 ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 : each-percent ( seq quot -- )