1	import Base
2	# Engine seam. Ordinary gameplay receives only canonical operation grants.
3	# Every action is invoked on both outcomes; no closure-held owner is discarded.
4	def Action(~State:Type,~Recovery:Type) -> Type:
5	  Bool -> State -> Recovery -> State & Recovery
6	def applied(~State:Type,~Recovery:Type,next:State -> Recovery -> State & Recovery,result:State & Recovery) -> State & Recovery:
7	  match result:
8	    case (state,recovery):next(state,recovery)
9	def finish(~State:Type,~Recovery:Type,journal:List<Action(~State,~Recovery)>,+success:Bool,state:State,recovery:Recovery) -> State & Recovery:
10	  match journal:
11	    case []:(state,recovery)
12	    case action <> rest:applied(~State,~Recovery,s => r => finish(~State,~Recovery,rest,success,s,r),action(success,state,recovery))