Changed visibility from package to interal

Sources/Engine/Pieces/Knight.swift

@@ -1,31 +1,54 @@
-package class Knight: Piece {
-	package weak var board: Board?
-	package var kind: Kind = .Knight
+internal final class Knight: Piece {
+	internal weak var board: Board?
+	internal var kind: Kind = .Knight
 
-	package var unicodeRepresentation: String {
+	internal var unicodeRepresentation: String {
 		return color == .Black ? "♞" : "♘"
 	}
-	package var color: Color
+	internal var color: Color
 
-	package var position: Square.Position
+	internal var position: Square.Position
 
-	package var pseudoLegalPositions: [Square.Position] {
-		return []
+	internal var pseudoLegalPositions: [Square.Position] {
+		let directions: [Square.Position] = [
+			.init(file: position.file + 1, rank: position.rank + 2),
+			.init(file: position.file - 1, rank: position.rank + 2),
+			.init(file: position.file + 1, rank: position.rank - 2),
+			.init(file: position.file - 1, rank: position.rank - 2),
+			.init(file: position.file + 2, rank: position.rank + 1),
+			.init(file: position.file - 2, rank: position.rank + 1),
+			.init(file: position.file + 2, rank: position.rank - 1),
+			.init(file: position.file - 2, rank: position.rank - 1)
+		]
+		return directions.filter {
+			let index = $0.index
+			return index < 0 || index > 63
+		}
 	}
 
-	package var legalPositions: [Square.Position] {
-		return pseudoLegalPositions.filter { isLegal(pos: $0) }
+	internal var legalPositions: [Square.Position] {
+		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	package func move(dst: Square.Position) -> Bool {
+	internal func move(to dst: Square.Position) -> Bool {
 		return false
 	}
 
-	package func isLegal(pos: Square.Position) -> Bool {
-		return false
+	internal func isLegal(on pos: Square.Position) -> Bool {
+		if let board = board, let s = board[pos] {
+			if let p = s.piece {
+				if p.color == color { return false }
+				if p.kind == .King {
+					// TODO: Notify board of check
+					return false
+				}
+			}
+
+		}
+		return true
 	}
 
-	package init(color: Color, on position: Square.Position) {
+	internal init(color: Color, on position: Square.Position) {
 		self.color = color
 		self.position = position
 	}