Concurrency.par_map.list.go: def of bend-kit-concurrency@0.2.0.0
Import: import bend-kit-concurrency@0.2.0.0/concurrency.bend as Concurrency
Lines 43-59 of bend-kit-concurrency@0.2.0.0/concurrency.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-concurrency@0.2.0.0/concurrency.bend&start_line=43&end_line=59

import Base

# lr holds two halves of nl and nr elements. Depth d runs 2^(d+1) parallel parts.
def par_map.list.go(
  ~A: Type, ~B: Type, ~f: A -> B, d: Nat, +nl: Nat, +nr: Nat, lr: List<A> & List<A>
) -> List<B>:
  match d:
    case 0n:
      (l, r) = lr
      lo hi = List.map(~A, ~B, ~f, l) List.map(~A, ~B, ~f, r)
      List.append(&1, B, lo, hi)
    case 1n+ +p:
      (l, r) = lr
      +hl = Nat.div(nl, 2n)
      +hr = Nat.div(nr, 2n)
      ls = split(A, l, hl)
      rs = split(A, r, hr)
      lo hi = par_map.list.go(~A, ~B, ~f, p, hl, Nat.sub(nl, hl), ls) par_map.list.go(~A, ~B, ~f, p, hr, Nat.sub(nr, hr), rs)
      List.append(&1, B, lo, hi)

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.map
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.div
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma
  https://jend.leeeet.dev/definition.txt?path=bend-kit-concurrency@0.2.0.0/concurrency.bend&name=split