PROOF.h.get_join: def of bend-kit-collections@0.1.4.1
Import: import bend-kit-collections@0.1.4.1/PROOF.bend as PROOF
Lines 2810-2833 of bend-kit-collections@0.1.4.1/PROOF.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-collections@0.1.4.1/PROOF.bend&start_line=2810&end_line=2833

import Base
import bend-kit-collections@0.1.4.1/hmap.bend as M

def h.get_join(
  ~K: Data, ~V: Data, ~eq: K -> K -> Bool, +p: Nat, +mask: U32, lo: M.HMap<K, V>,
  hi: M.HMap<K, V>, +hk: U32, +k: K
) -> {h.G(~K, ~V, ~eq, 1n+p, mask, M.HBranch{lo, hi}, hk, k)
      == h.G(~K, ~V, ~eq, 1n+p, mask, M.HMap.join(K, V, lo, hi), hk, k) : Maybe<&2, V>}:
  match lo:
    case M.HNil{}:
      match hi:
        case M.HNil{}:
          Equal.sym(Maybe<&2, V>, None{},
            M.HMap.bool(Maybe<&2, V>, U32.is_eq((hk .&. mask : U32), 0),
              u => h.G(~K, ~V, ~eq, p, (mask << 1n : U32), M.HNil{}, hk, k),
              u => h.G(~K, ~V, ~eq, p, (mask << 1n : U32), M.HNil{}, hk, k)),
            h.bnn(V, U32.is_eq((hk .&. mask : U32), 0),
              h.G(~K, ~V, ~eq, p, (mask << 1n : U32), M.HNil{}, hk, k),
              h.gnil(~K, ~V, ~eq, p, (mask << 1n : U32), hk, k)))
        case M.HLeaf{a, b}:
          {==}
        case M.HBranch{a, b}:
          {==}
    case M.HLeaf{a, b}:
      {==}
    case M.HBranch{a, b}:
      {==}

Uses (14):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.shln
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/PROOF.bend&name=h.G
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/PROOF.bend&name=h.bnn
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/PROOF.bend&name=h.gnil
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/hmap.bend&name=HMap
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/hmap.bend&name=HMap.bool
  https://jend.leeeet.dev/definition.txt?path=bend-kit-collections@0.1.4.1/hmap.bend&name=HMap.join