Sliding pieces moves are now illegal if after piece of same color

Sources/exe/main.swift

@@ -7,6 +7,7 @@ enum Command: Equatable {
 	case move(from: String, to: String)
 	case history(command: String? = nil)
 	case highlightThreatened(color: Color)
+	case highlightPositions(of: Square.Position)
 
 	init?(rawValue: String) {
 		let args = rawValue.lowercased().split(separator: " ")
@@ -28,16 +29,25 @@ enum Command: Equatable {
 		case "history", "h":
 			self = .history()
 		case "highlight" where args.count == 2, "hi" where args.count == 2:
-			let color: Color =
+			let color: Color? =
 				switch args[1] {
 				case "w", "white":
 					.White
 				case "b", "black":
 					.Black
 				default:
-					.White
+					nil
 				}
-			self = .highlightThreatened(color: color)
+			if let c = color {
+				self = .highlightThreatened(color: c)
+				return
+			}
+
+			if let position = try? Square.Position(with: String(args[1])) {
+				self = .highlightPositions(of: position)
+				return
+			}
+			return nil
 		default:
 			return nil
 		}
@@ -81,6 +91,14 @@ while command != .quit {
 				print(ts.count)
 				print(board.text(with: [color: Array(ts)]))
 			}
+		case .highlightPositions(let pos):
+			if let square = board.getSquareInfo(on: pos),
+				let piece =
+					square.piece
+			{
+				let color = Board.TerminalColors(fg: .def, bg: .green)
+				print(board.text(with: [color: piece.legalPositions]))
+			}
 		}
 	}
 }