Added commands to execute interactively

Sources/Engine/Pieces/Piece.swift

@@ -55,7 +55,6 @@ public enum Kind: String, CaseIterable {
 
 public class Piece: Hashable {
 	#warning("TODO: To be removed, handle everything through the delegate")
-	internal weak var board: Board?
 	public internal(set) var color: Color
 	public internal(set) var halfMoveCount: UInt8 = 0
 	public var unicodeRepresentation: String {
@@ -73,7 +72,7 @@ public class Piece: Hashable {
 	internal var delegate: EventDelegate?
 
 	internal func move(to dst: Square.Position) throws {
-		if !(legalPositions.contains { $0 == dst }) {
+		guard (legalPositions.contains { $0 == dst }) else {
 			throw Board.MoveFailure.destinationIsIllegal(pos: dst)
 		}
 
@@ -83,7 +82,7 @@ public class Piece: Hashable {
 
 	#warning("This method should be better thought out.")
 	internal func isLegal(on pos: Square.Position) -> Bool {
-		if let board = board, let s = board[pos] {
+		if let s = delegate?.getSquareInfo(on: pos) {
 			if let p = s.piece {
 				if p.color == color { return false }
 				if let king = p as? King {