def rollback

bendvy-ecs-core@0.1.0.4 · transaction.bend:61

import Base

61# Trusted lower-level journal execution: apply inverse closures head first
62# and return World. Only recorded changes are undone; no general mutation or
63# external-effect rollback is inferred from calling this function.
64def rollback(~W: Type, undo: List<&1, (W -> W)>, world: W) -> W:
65  match undo:
66    case Nil{}:
67      world
68    case Con{inverse, rest}:
69      rollback(~W, rest, inverse(world))