Pawn moves

Sources/Engine/Pieces/Pawn.swift

@@ -1,6 +1,8 @@
 final class Pawn: Piece {
+	private var sign: Int8 {
+		color == .Black ? -1 : 1
+	}
 	override var pseudoLegalPositions: [Square.Position] {
-		let sign: Int8 = color == .Black ? -1 : 1
 		return [
 			position + (1 * sign, 0),
 			position + (2 * sign, 0),
@@ -14,7 +16,25 @@ final class Pawn: Piece {
 	}
 
 	override func isLegal(on pos: Square.Position) -> Bool {
-		super.isLegal(on: pos)
+		#warning("Handle en-passant")
+		if pos == position + (2 * sign, 0) && halfMoveCount > 0 {
+			return false
+		}
+		if (pos == position + (1 * sign, 0) || pos == position + (2 * sign, 0))
+			&& delegate?.getSquareInfo(on: pos)?.piece != nil
+		{
+			return false
+		}
+		guard super.isLegal(on: pos) else {
+			return false
+		}
+		if (pos == position + (1 * sign, 1) || pos == position + (1 * sign, -1))
+			&& delegate?.getSquareInfo(on: pos)?.piece == nil
+		{
+			return false
+		}
+
+		return true
 	}
 
 	init(with color: Color, on position: Square.Position) {