law walk_safe

minebender-game@1.0.0.0 · proof_walk.bend:178

import Base
import minebender-game@1.0.0.0/types.bend as T
import minebender-game@1.0.0.0/LAWS.bend as L

178# A walk from a safe cell only reaches safe cells.
179law walk_safe:
180  for +path: List<&2, T.Pos>
181  for +w: Nat
182  for +h: Nat
183  for +layout: T.Grid(Bool)
184  for +s: T.Pos
185  for +q: T.Pos
186  for +wk: {L.zero_walk(path, w, h, layout, s, q) == True{} : Bool}
187  for +safe: {L.mine(layout, s) == False{} : Bool}
188  {L.mine(layout, q) == False{} : Bool}