Merged in better-communication (pull request #49)

Better communication

Shogi.Domain/Pieces/Bishop.cs

@@ -0,0 +1,47 @@
+using Shogi.Domain.Pathing;
+using System.Collections.ObjectModel;
+
+namespace Shogi.Domain.Pieces
+{
+	internal class Bishop : Piece
+	{
+		private static readonly ReadOnlyCollection<Path> BishopPaths = new(new List<Path>(4)
+		{
+			new Path(Direction.UpLeft, Distance.MultiStep),
+			new Path(Direction.UpRight, Distance.MultiStep),
+			new Path(Direction.DownLeft, Distance.MultiStep),
+			new Path(Direction.DownRight, Distance.MultiStep)
+		});
+
+		public static readonly ReadOnlyCollection<Path> PromotedBishopPaths = new(new List<Path>(8)
+		{
+			new Path(Direction.Up),
+			new Path(Direction.Left),
+			new Path(Direction.Right),
+			new Path(Direction.Down),
+			new Path(Direction.UpLeft, Distance.MultiStep),
+			new Path(Direction.UpRight, Distance.MultiStep),
+			new Path(Direction.DownLeft, Distance.MultiStep),
+			new Path(Direction.DownRight, Distance.MultiStep)
+		});
+
+		public static readonly ReadOnlyCollection<Path> Player2Paths =
+			BishopPaths
+			.Select(p => p.Invert())
+			.ToList()
+			.AsReadOnly();
+
+		public static readonly ReadOnlyCollection<Path> Player2PromotedPaths =
+			PromotedBishopPaths
+			.Select(p => p.Invert())
+			.ToList()
+			.AsReadOnly();
+
+		public Bishop(WhichPlayer owner, bool isPromoted = false)
+			: base(WhichPiece.Bishop, owner, isPromoted)
+		{
+		}
+
+		public override IEnumerable<Path> MoveSet => IsPromoted ? PromotedBishopPaths : BishopPaths;
+	}
+}