hoon: add +roll

2024-11-23 00:25:49 +03:00 · 2023-09-05 13:16:02 -06:00 · 2023-09-05 13:16:02 -06:00 · ff2650cf3a
commit ff2650cf3a
parent 304f399595
1 changed files with 8 additions and 0 deletions
--- a/hoon/scaffolding/playpen.hoon
+++ b/hoon/scaffolding/playpen.hoon
@ -229,6 +229,14 @@
  ?~  a  ~
  [b $(a (dec a))]
 ::
++  roll                                                ::  left fold
+  ~/  %roll
+  |*  [a=(list) b=_=>(~ |=([* *] +<+))]
+  |-  ^+  ,.+<+.b
+  ?~  a
+    +<+.b
+  $(a t.a, b b(+<+ (b i.a +<+.b)))
+::
 ++  slag                                                ::  suffix
  ~/  %slag
  |*  [a=@ b=(list)]