anchor.diff:          Setters.Add ("PublishUpdates", fun _ _ world -> (false, world))
           Setters.Add ("PublishPostUpdates", fun _ _ world -> (false, world))
           Setters.Add ("Persistent", fun property entity world -> (true, World.setEntityPersistent (property.PropertyValue :?> bool) entity world))
  -        Setters.Add ("StandAlone", fun property entity world -> (true, World.setEntityStandAlone (property.PropertyValue :?> bool) entity world))
           Setters.Add ("OverlayNameOpt", fun _ _ world -> (false, world))
           Setters.Add ("FacetNames", fun _ _ world -> (false, world))
           Setters.Add ("CreationTimeStamp", fun _ _ world -> (false, world))
  
positive.code:         static member internal setEntityPublishUpdates value entity world = World.updateEntityState (fun entityState -> if value <> entityState.PublishUpdates then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.PublishUpdates <- value; entityState) else None) false Property? PublishUpdates value entity world
          static member internal setEntityPublishPostUpdates value entity world = World.updateEntityState (fun entityState -> if value <> entityState.PublishPostUpdates then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.PublishPostUpdates <- value; entityState) else None) false Property? PublishPostUpdates value entity world
          static member internal setEntityPersistent value entity world = World.updateEntityState (fun entityState -> if value <> entityState.Persistent then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.Persistent <- value; entityState) else None) false Property? Persistent value entity world
          static member internal setEntityStandAlone value entity world = World.updateEntityState (fun entityState -> if value <> entityState.StandAlone then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.StandAlone <- value; entityState) else None) false Property? StandAlone value entity world
          static member internal setEntityOverflow value entity world = World.updateEntityStatePlus (fun entityState -> if v2Neq value entityState.Overflow then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.Overflow <- value; entityState) else None) false Property? Overflow value entity world
          static member internal setEntityScriptFrame value entity world = World.updateEntityState (fun entityState -> if value <> entityState.ScriptFrame then Some (let entityState = if entityState.ShouldMutate then entityState else EntityState.diverge entityState in entityState.ScriptFrame <- value; entityState) else None) false Property? ScriptFrame value entity world
  
  
negative.code: 
              // HACK: make sure xtension is consistent with imperativeness of entity state
              let world = World.setEntityImperative entityState.Imperative entity world
              (entity, world)
  
          /// Read an entity from a file.
  