anchor.diff:      static member containsPickup (fieldSpace : FieldSpace) =
           fieldSpace.ContainsPickup
   
  -    // internal
  +    // internal updaters
       
       static member updateCharacterOpt updater fieldSpace =
           { fieldSpace with CharacterOpt = updater fieldSpace.CharacterOpt }
  
positive.code:         Gameplay.updateCharacterTurn index (Turn.updateTurnStatus (constant status)) gameplay
      
      static member updateCharacter index updater gameplay =
          Gameplay.updateChessboardBy Chessboard.updateCharacter index updater gameplay
  
      static member relocateCharacter index coordinates gameplay =
          Gameplay.updateChessboardBy Chessboard.relocateCharacter index coordinates gameplay
      
      static member addHealth coordinates gameplay =
          Gameplay.updateChessboardBy Chessboard.addHealth () coordinates gameplay
  
      static member removeHealth coordinates gameplay =
          Gameplay.updateChessboardBy Chessboard.removePickup () coordinates gameplay
      
      static member clearPickups gameplay =
          Gameplay.updateChessboardBy Chessboard.clearPickups () () gameplay
      
      static member removeEnemy index gameplay =
          let coordinates = Gameplay.getCoordinates index gameplay
          let gameplay = Gameplay.addHealth coordinates gameplay
          Gameplay.updateChessboardBy Chessboard.removeCharacter index () gameplay
  
      static member clearEnemies gameplay =
          Gameplay.updateChessboardBy Chessboard.clearEnemies () () gameplay
  
      static member finishMove index gameplay =
          let gameplay = Gameplay.updateCharacterTurns (fun turns -> List.filter (fun x -> x.Actor <> index) turns) gameplay
  
negative.code:         Gameplay.updateCharacterTurns (fun x -> turn :: x) gameplay
  
      static member setFieldMap fieldMap gameplay =
          let gameplay = Gameplay.updateChessboard (Chessboard.setFieldSpaces fieldMap) gameplay
          let field = { FieldMapNp = fieldMap }
          Gameplay.updateField (constant field) gameplay
  
      static member resetFieldMap fieldMap gameplay = // TODO: get rid of this redundency
          let gameplay = Gameplay.updateChessboard (Chessboard.transitionMap fieldMap) gameplay
          let field = { FieldMapNp = fieldMap }
          Gameplay.updateField (constant field) gameplay
      
  