Currently i am implementing Sokoban and i was pondering which methods i should add to my Cell class:

• bool HoldsWall
• bool HoldsBox
• bool HoldsPlayer

Or

• bool HoldsPieceOfType(Type type)

Which option should i choose? With the aid of extension methods (in the same namespace) i can have them both:

namespace Sokoban.Domain
{
	public static class ExtensionMethods
	{
		public static bool HoldsBox(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Box));
		}

		public static bool HoldsPlayer(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Player));
		}

		public static bool HoldsWall(this Cell cell)
		{
			return cell.HoldsPieceOfType(typeof(Wall));
		}
	}
}

In case you don’t like this solution, blame Brad Abrams who inspired me to implement it this way with his session at Visug yesterday.

Remark: Because the possible pieces in Sokoban are very well known (the game/requirements are not going to change) thus one should choose the first option (No extension methods required.)