public override IEnumerable <Position> Execute(BrainfuckEnv be) { yield return(_pos); switch (_char) { case '+': be.Inc(); break; case '-': be.Dec(); break; case '<': be.MoveLeft(); break; case '>': be.MoveRight(); break; case '.': be.BfOutput(); break; case ',': be.BfInput(); break; default: break; } }