MlbendGenerative.groups_of: def of mlbend-generative@0.1.1.0
Import: import mlbend-generative@0.1.1.0/main.bend as MlbendGenerative
Lines 275-288 of mlbend-generative@0.1.1.0/main.bend: https://jend.leeeet.dev/read.txt?path=mlbend-generative@0.1.1.0/main.bend&start_line=275&end_line=288

import Base

# How many entries the walk emits over n entries. The count recurses on
# the count left, exactly as the walk recurses on the list left, and the
# two matches (on the count, on the skip) are in the same order — that
# is what lets the law below follow both by induction.
def groups_of(+n: Nat, +k: Nat, +skip: Nat) -> Nat:
  match n:
    case 0n:
      0n
    case 1n+m:
      match skip:
        case 0n:
          (1n + groups_of(m, k, Nat.sub(k, 1n)) : Nat)
        case 1n+r:
          groups_of(m, k, r)

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub