law step_val

lawful-bytes@0.1.1.0 · proof_same.bend:108

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

108# One step of a read loop at index s with n + 1 left, within a Bytes of size len:
109# byte s is read, s + 1 does not wrap, and the bound holds one index on.
110law step_val:
111  for +len: U32
112  for +t: P.Tree<U32>
113  for +d: Nat
114  for +s: U32
115  for +m: Nat
116  for +h: {D.ok(C.BT(len, t), d) == True{} : Bool}
117  for +hs: {Nat.is_le(Nat.add(U32.to_nat(s), 1n+m), U32.to_nat(len)) == True{} : Bool}
118  {List.get(&2, U32, D.view(C.BT(len, t)), U32.to_nat(s)) == Some{C.AT(len, t, s)} : Maybe<&2, U32>}