law step_get

lawful-bytes@0.1.1.0 · proof_find.bend:229

import Base
import lawful-bytes@0.1.1.0/defs.bend as D
import lawful-bytes@0.1.1.0/proof_core.bend as C
import lawful-arrays@0.1.0.0/proof_tree.bend as P

229law step_get:
230  for +len: U32
231  for +t: P.Tree<U32>
232  for +d: Nat
233  for +j: U32
234  for +h: {D.ok(C.BT(len, t), d) == True{} : Bool}
235  for +hj: {Nat.is_lt(U32.to_nat(j), U32.to_nat(len)) == True{} : Bool}
236  {List.get(&2, U32, D.view(C.BT(len, t)), U32.to_nat(j)) == Some{C.AT(len, t, j)} : Maybe<&2, U32>}