Remove redundant equatable conformances and make Game and MoveTree ha…

…shable

CHANGELOG.md

@@ -1,6 +1,7 @@
 # [unreleased]
 
 ### Improvements
+* Conform more types to `Hashable` such as `Game` and `MoveTree`.
 * `Game.Tag` now publicly exposes `name`.
 * `Game.Tags` is now `Hashable` and `Sendable`.
 

Sources/ChessKit/Bitboards/PieceSet.swift

@@ -7,7 +7,7 @@
 ///
 /// Also contains convenient amalgamations
 /// of different combinations of pieces.
-struct PieceSet: Equatable, Hashable, Sendable {
+struct PieceSet: Hashable, Sendable {
     /// Bitboard for black king pieces.
     var k: Bitboard = 0
     /// Bitboard for black queen pieces.

Sources/ChessKit/Board.swift

@@ -567,7 +567,7 @@ public struct Board: Sendable {
 
 extension Board {
     /// Represents an end result of a standard chess game.
-    public enum EndResult: Equatable, Sendable {
+    public enum EndResult: Hashable, Sendable {
         /// The board represents a win for the given color.
         case win(Piece.Color)
         /// The board represents a draw with a given reason.

Sources/ChessKit/Clock.swift

@@ -5,7 +5,7 @@
 
 /// Tracks the number of moves in a game for
 /// the purposes of regulating the 50 move rule.
-public struct Clock: Equatable, Sendable {
+public struct Clock: Hashable, Sendable {
 
     /// The maximum number of half moves before
     /// a draw by the fifty move rule should be called.

Sources/ChessKit/Game.swift

@@ -10,7 +10,7 @@ import Foundation
 /// This object is the entry point for interacting with a full
 /// chess game within `ChessKit`. It provides methods for
 /// making moves and publishes the played moves in an observable way.
-public struct Game: Equatable {
+public struct Game: Hashable {
 
     // MARK: - Properties
 
@@ -206,7 +206,7 @@ extension Game {
 
     /// Denotes a PGN tag pair.
     @propertyWrapper
-    public struct Tag: Equatable, Hashable, Sendable {
+    public struct Tag: Hashable, Sendable {
 
         /// The name of the tag pair.
         ///
@@ -232,7 +232,7 @@ extension Game {
     }
 
     /// Contains the PGN tag pairs for a game.
-    public struct Tags: Equatable, Hashable, Sendable {
+    public struct Tags: Hashable, Sendable {
 
         /// Whether or not all the standard mandatory tags for
         /// PGN archival are set.

Sources/ChessKit/Move.swift

@@ -3,10 +3,10 @@
 //  ChessKit
 //
 
-public struct Move: Equatable, Hashable, Sendable {
+public struct Move: Hashable, Sendable {
 
     /// The result of the move.
-    public enum Result: Equatable, Hashable, Sendable {
+    public enum Result: Hashable, Sendable {
         case move
         case capture(Piece)
         case castle(Castling)
@@ -29,7 +29,7 @@ public struct Move: Equatable, Hashable, Sendable {
     }
 
     /// Rank, file, or square disambiguation of moves.
-    public enum Disambiguation: Equatable, Hashable, Sendable {
+    public enum Disambiguation: Hashable, Sendable {
         case byFile(Square.File)
         case byRank(Square.Rank)
         case bySquare(Square)

Sources/ChessKit/MoveTree/MoveTree.swift

@@ -7,7 +7,7 @@
 ///
 /// The tree maintains the move order including variations and
 /// provides index-based access for any element in the tree.
-public struct MoveTree {
+public struct MoveTree: Hashable {
 
     /// The index of the root of the move tree.
     ///
@@ -263,7 +263,7 @@ public struct MoveTree {
 
     /// An element for representing the ``MoveTree`` in
     /// PGN (Portable Game Notation) format.
-    public enum PGNElement: Hashable, Equatable, Sendable {
+    public enum PGNElement: Hashable, Sendable {
         /// e.g. `1.`
         case whiteNumber(Int)
         /// e.g. `1...`
@@ -340,7 +340,7 @@ extension MoveTree: Equatable {
 extension MoveTree {
 
     /// Object that represents a node in the move tree.
-    class Node: Equatable {
+    class Node: Hashable {
 
         /// The move for this node.
         var move: Move
@@ -362,6 +362,15 @@ extension MoveTree {
             lhs.index == rhs.index && lhs.move == rhs.move
         }
 
+        // MARK: - Hashable
+        func hash(into hasher: inout Hasher) {
+            hasher.combine(move)
+            hasher.combine(index)
+            hasher.combine(previous)
+            hasher.combine(next)
+            hasher.combine(children)
+        }
+
     }
 
 }

Sources/ChessKit/Piece.swift

@@ -4,7 +4,7 @@
 //
 
 /// Represents a piece on the chess board.
-public struct Piece: Equatable, Hashable, Sendable {
+public struct Piece: Hashable, Sendable {
 
     /// Represents the color of a piece.
     public enum Color: String, CaseIterable, Sendable {

Sources/ChessKit/Position.swift

@@ -4,7 +4,7 @@
 //
 
 /// Represents the collection of pieces on the chess board.
-public struct Position: Equatable, Sendable {
+public struct Position: Sendable {
 
     /// The pieces currently existing on the board in this position.
     public var pieces: [Piece] {
@@ -210,6 +210,7 @@ public struct Position: Equatable, Sendable {
 
 }
 
+// MARK: - Sample positions
 extension Position {
     /// A random chess position that can be used for testing.
     public static let test = Position(pieces: [
@@ -227,6 +228,7 @@ extension Position {
     public static let standard = Position(fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")!
 }
 
+// MARK: - CustomStringConvertible
 extension Position: CustomStringConvertible {
 
     public var description: String {
@@ -235,6 +237,7 @@ extension Position: CustomStringConvertible {
 
 }
 
+// MARK: - Hashable
 extension Position: Hashable {
 
     public func hash(into hasher: inout Hasher) {

Sources/ChessKit/Special Moves/Castling.swift

@@ -4,7 +4,7 @@
 //
 
 /// Structure that captures legal castling moves.
-struct LegalCastlings: Equatable, Hashable, Sendable {
+struct LegalCastlings: Hashable, Sendable {
 
     private var legal: [Castling]
 
@@ -55,7 +55,7 @@ struct LegalCastlings: Equatable, Hashable, Sendable {
 ///
 /// Contains various characteristics of the castling move
 /// such as king and rook start and end squares and notation.
-public struct Castling: Equatable, Hashable, Sendable {
+public struct Castling: Hashable, Sendable {
 
     /// Kingside castle for black.
     static let bK = Castling(side: .king, color: .black)

Sources/ChessKit/Special Moves/EnPassant.swift

@@ -4,7 +4,7 @@
 //
 
 /// Structure that captures en passant moves.
-struct EnPassant: Equatable, Hashable, Sendable {
+struct EnPassant: Hashable, Sendable {
 
     /// Pawn that is capable of being captured by en passant.
     var pawn: Piece

Sources/ChessKit/Square.swift

@@ -3,7 +3,7 @@
 //  ChessKit
 //
 
-public enum Square: Int, Equatable, CaseIterable, Sendable {
+public enum Square: Int, CaseIterable, Sendable {
     /// The file on the chess board, from a to h.
     public enum File: String, CaseIterable, Sendable {
         case a, b, c, d, e, f, g, h
@@ -45,7 +45,7 @@ public enum Square: Int, Equatable, CaseIterable, Sendable {
     }
 
     /// The rank on the chess board, from 1 to 8.
-    public struct Rank: ExpressibleByIntegerLiteral, Equatable, Hashable, Sendable {
+    public struct Rank: ExpressibleByIntegerLiteral, Hashable, Sendable {
         /// The possible range of Rank numbers.
         public static let range = 1...8