Inductive ruleMatchesR : subject -> object -> action -> rule -> Prop :=
  RM_Matches : forall s o a r,
    exprMatchSubjectEvalR s (rMatchSubject r) ->
      exprMatchObjectEvalR o (rMatchObject r) ->
        exprMatchActionEvalR a (rMatchAction r) ->
          ruleMatchesR s o a r.
