Reconstruction.divide: def of bend-edit-distance@0.2.2.0
Import: import bend-edit-distance@0.2.2.0/src/Reconstruction.bend as Reconstruction
Lines 173-202 of bend-edit-distance@0.2.2.0/src/Reconstruction.bend: https://jend.leeeet.dev/read.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&start_line=173&end_line=202

import Base
import bend-edit-distance@0.2.2.0/EdlibTypes.bend as E

# The fuel is the initial row length; every nonbase call halves that length.
# Score passes run in balanced parallel calls and are consumed before recursion.
# Subpaths are evaluated sequentially to bound live score storage even on many
# threads; the result lists themselves necessarily use O(m+n) space.
def divide(fuel: Nat, +query: String, +target: String, +query_length: Nat,
             +target_length: Nat, +pairs: List<&2, E.EqualityPair>, small: Bool) ->
             List<&2, E.Operation>:
  match fuel query target small:
    case _ SNil{} _ _:
      List.replicate(E.Operation, target_length, E.Delete{})
    case _ _ SNil{} _:
      List.replicate(E.Operation, query_length, E.Insert{})
    case 0n _ _ _:
      dp(query, target, pairs)
    case 1n+p SCon{_, SNil{}} _ _:
      dp(query, target, pairs)
    case 1n+p _ _ True{}:
      dp(query, target, pairs)
    case Succ{+p} _ _ False{}:
      +half = Nat.div(query_length, 2n)
      +left = String.take(query, half)
      +right = String.drop(query, half)
      +cut = midpoint(left, right, target, pairs)
      left_path = divide(p, left, String.take(target, cut), half, cut, pairs,
        small_matrix(half, cut))
      +right_length = Nat.sub(query_length, half)
      +right_width = Nat.sub(target_length, cut)
      right_path = divide(p, right, String.drop(target, cut), right_length, right_width, pairs,
        small_matrix(right_length, right_width))
      List.append(&2, E.Operation, left_path, right_path)

Uses (15):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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.replicate
  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=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.drop
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.take
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/EdlibTypes.bend&name=EqualityPair
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/EdlibTypes.bend&name=Operation
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=dp
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=midpoint
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Reconstruction.bend&name=small_matrix