moved everything related to python in the python

folder

python/src/logic/board.py

@@ -0,0 +1,360 @@
+from logic.move import CastleSide, Move
+from logic.pieces.bishop import Bishop
+from logic.pieces.king import King
+from logic.pieces.knight import Knight
+from logic.pieces.queen import Queen
+from logic.pieces.rook import Rook
+from logic.pieces.pawn import Pawn
+from logic.pieces.piece import Colour, Piece
+from logic.position import Position
+
+from typing import Type
+
+class Board:
+    def __init__(self) -> None:
+        self._white: dict[Position, Piece] = {}
+        self._black: dict[Position, Piece] = {}
+        self._turn = None
+        self._white_castling_rights = set()
+        self._black_castling_rights = set()
+        self._en_passant_target = None
+        self._n_moves = 0
+        self._n_half_moves = 0
+
+    @staticmethod
+    def _piece_class_from_char(c: str) -> Type[Piece]:
+        assert len(c) == 1, f"The piece {c} isn't denoted by 1 character"
+        c = c.lower()
+        if c == "p":
+            return Pawn
+        if c == "r":
+            return Rook
+        if c == "n":
+            return Knight
+        if c == "b":
+            return Bishop
+        if c == "q":
+            return Queen
+        if c == "k":
+            return King
+        raise ValueError(f"Unknown piece '{c}'")
+
+    @staticmethod
+    def setup_FEN_position(position: str) -> "Board":
+        ret = Board()
+        index = 0
+
+        # -- Pieces
+        pieces = "prnbqk" # possible pieces
+        numbers = "12345678" # possible number of empty squares
+
+        x = 0
+        y = 7 # FEN starts from the top left, so 8th rank
+        for c in position:
+            index += 1
+            if c == " ":
+                break
+            if c in pieces or c in pieces.upper():
+                pos = Position(x, y)
+                piece = Board._piece_class_from_char(c)
+                if c.isupper():
+                    ret._white[pos] = piece(pos, Colour.WHITE)
+                else:
+                    ret._black[pos] = piece(pos, Colour.BLACK)
+
+                x += 1
+                continue
+            if c in numbers:
+                x += int(c)
+            if c == '/':
+                x = 0
+                y -= 1
+
+
+        # -- Active colour
+        if position[index] == "w":
+            ret._turn = Colour.WHITE
+        elif position[index] == "b":
+            ret._turn = Colour.BLACK
+        else:
+            raise ValueError(f"The FEN position is malformed, the active colour should be either 'w' or 'b', but is '{position[index]}'")
+        index += 2
+
+
+        # -- Castling Rights
+        for c in position[index:]:
+            index += 1
+            if c == "-" or c == " ":
+                if c == "-":
+                    index += 1
+                break
+
+            sides = "kq"
+            assert c in sides or c in sides.upper(), f"The FEN position is malformed, the castling rights should be either k or q (both either lower- or upper-case), instead is '{c}'"
+            if c == "K":
+                ret._white_castling_rights.add(CastleSide.King)
+            if c == "Q":
+                ret._white_castling_rights.add(CastleSide.Queen)
+            if c == "k":
+                ret._black_castling_rights.add(CastleSide.King)
+            if c == "q":
+                ret._black_castling_rights.add(CastleSide.Queen)
+
+        # -- En passant target
+        if position[index] != "-":
+            pos = Position.from_algebraic(position[index:index+2]) 
+            index += 2
+            if pos.y == 2:
+                pos.y += 1
+                assert pos in ret._white, "En passant target is not in the position"
+                ret._en_passant_target = ret._white[pos]
+            elif pos.y == 5:
+                pos.y -= 1
+                assert pos in ret._black, "En passant target is not in the position"
+                ret._en_passant_target = ret._black[pos]
+            else:
+                raise ValueError("You can't have a en passant target that is not on the third or sixth rank")
+        else:
+            index += 1
+        index += 1
+
+        ret._n_half_moves = int(position[index:position.find(" ", index + 1)])
+        ret._n_moves = int(position[position.find(" ", index)+1:])
+
+        return ret
+
+    def piece_at(self, x: int, y: int) -> Piece | None:
+        pos = Position(x, y)
+        white_piece = self._white.get(pos, None)
+        black_piece = self._black.get(pos, None)
+
+        assert white_piece == None or black_piece == None, f"There are two pieces at the same position {pos}, this shouldn't happen!"
+
+        if white_piece != None:
+            return white_piece
+        return black_piece
+
+    def is_check_for(self, colour: Colour) -> bool:
+        """ Is it check for the defending colour passed as parameter """
+        defending_pieces, attacking_pieces = (self._white, self._black) if colour == Colour.WHITE else (self._black, self._white)
+
+        kings = [piece for piece in defending_pieces.values() if type(piece) == King]
+        assert len(kings) == 1, f"We have more than one king for {colour}, that is no buono..."
+        king = kings[0]
+
+        for piece in attacking_pieces.values():
+            possible_pos = []
+            if type(piece) == King: 
+                # special case for the king, because it creates infinite recursion (since he looks if he's walking into a check)
+                for dx in [-1, 0, 1]:
+                    for dy in [-1, 0, 1]:
+                        x, y = piece.pos.x + dx, piece.pos.y + dy
+                        if Position.is_within_bounds(x, y):
+                            possible_pos.append(Position(x, y))
+            else:
+                possible_pos += [move.pos for move in piece.legal_moves(self, looking_for_check=True)]
+            if king.pos in possible_pos:
+                return True
+        return False
+
+    def is_checkmate_for(self, colour: Colour) -> bool:
+        """ Is it checkmate for the defending colour passed as parameter """
+        return self.is_check_for(colour) and self._no_legal_moves_for(colour)
+
+    def is_stalemate_for(self, colour: Colour) -> bool:
+        """ Is it stalemate for the defending colour passed as parameter """
+        return not self.is_check_for(colour) and self._no_legal_moves_for(colour)
+
+    def _no_legal_moves_for(self, colour: Colour) -> bool:
+        """ Return true if there are indeed no legal moves for the given colour (for checkmate or stalemate)"""
+        pieces = self._white if colour == Colour.WHITE else self._black
+        for piece in pieces.values():
+            if len(piece.legal_moves(self)) > 0:
+                return False
+        return True
+
+    def castling_rights_for(self, colour: Colour) -> set[CastleSide]:
+        return self._white_castling_rights if colour == Colour.WHITE else self._black_castling_rights
+
+    def make_move(self, move: Move) -> "Board":
+        dest_piece = self.piece_at(move.pos.x, move.pos.y) 
+
+        if dest_piece:
+            assert dest_piece.colour != move.piece.colour, "A piece cannot cannot eat another piece of the same colour"
+
+        # -- Copy current state
+        ret = Board()
+        ret._white = self._white.copy()
+        ret._black = self._black.copy()
+        ret._turn = Colour.WHITE if self._turn == Colour.BLACK else Colour.BLACK
+        ret._white_castling_rights = self._white_castling_rights.copy()
+        ret._black_castling_rights = self._black_castling_rights.copy()
+
+
+        piece = move.piece
+
+        # -- Actually make the move
+        pieces_moving, other_pieces = (ret._white, ret._black) if piece.colour == Colour.WHITE else (ret._black, ret._white)
+
+        del pieces_moving[piece.pos]
+        pieces_moving[move.pos] = piece.move_to(move.pos)
+        if move.pos in other_pieces:
+            del other_pieces[move.pos]
+
+        if piece.colour == Colour.BLACK:
+            ret._n_moves = self._n_moves + 1
+
+        if move.is_capturing or type(piece) == Pawn:
+            ret._n_half_moves = 0
+        else:
+            ret._n_half_moves = self._n_half_moves + 1
+
+        if move.en_passant:
+            pos_to_remove = Position(move.pos.x, move.pos.y + (1 if self._turn == Colour.BLACK else -1))
+            del other_pieces[pos_to_remove]
+
+        if move.promotes_to is not None:
+            assert type(piece) == Pawn, "Trying to promote something that is not a pawn: not good!"
+            pieces_moving[move.pos] = move.promotes_to(move.pos, piece.colour)
+
+        # -- Set en passant target if needed
+        if move.becomes_en_passant_target:
+            ret._en_passant_target = pieces_moving[move.pos]
+        else:
+            ret._en_passant_target = None
+
+        # -- Handle castling (just move the rook over)
+        if move.castle_side == CastleSide.King:
+            rook_pos = Position(7, piece.pos.y)
+            assert rook_pos in pieces_moving and type(pieces_moving[rook_pos]) == Rook, "Either rook is absent from the king side or you are trying to castle with something else than a rook..."
+            del pieces_moving[rook_pos]
+            new_rook_pos = Position(5, piece.pos.y)
+            pieces_moving[new_rook_pos] = Rook(new_rook_pos, piece.colour)
+
+        elif move.castle_side == CastleSide.Queen:
+            rook_pos = Position(0, piece.pos.y)
+            assert rook_pos in pieces_moving and type(pieces_moving[rook_pos]) == Rook, "Either rook is absent from the queen side or you are trying to castle with something else than a rook..."
+            del pieces_moving[rook_pos]
+            new_rook_pos = Position(3, piece.pos.y)
+            pieces_moving[new_rook_pos] = Rook(new_rook_pos, piece.colour)
+
+        # -- Check for castling rights
+        if piece.colour == Colour.WHITE:
+            if type(piece) == King:
+                ret._white_castling_rights = set()
+
+            if type(piece) == Rook:
+                if piece.pos.x == 0 and CastleSide.Queen in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.Queen)
+                elif piece.pos.x == 7 and CastleSide.King in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.King)
+
+            if move.is_capturing and move.pos.y == 7 and move.pos in self._black and type(self._black[move.pos]) == Rook:
+                if move.pos.x == 0 and CastleSide.Queen in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.Queen)
+                elif move.pos.x == 7 and CastleSide.King in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.King)
+        else:
+            if type(piece) == King:
+                ret._black_castling_rights = set()
+
+            if type(piece) == Rook:
+                if piece.pos.x == 0 and CastleSide.Queen in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.Queen)
+                elif piece.pos.x == 7 and CastleSide.King in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.King)
+
+            if move.is_capturing and move.pos.y == 0 and move.pos in self._white and type(self._white[move.pos]) == Rook:
+                if move.pos.x == 0 and CastleSide.Queen in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.Queen)
+                elif move.pos.x == 7 and CastleSide.King in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.King)
+
+        return ret
+
+    def to_fen_string(self):
+        ret = ""
+        for y in range(7, -1, -1):
+            empty_cell_counter = 0
+            for x in range(8):
+                pos = Position(x, y)
+
+                piece = None
+                if pos in self._white:
+                    piece = self._white[pos]
+                elif pos in self._black:
+                    piece = self._black[pos]
+
+                if piece is None:
+                    empty_cell_counter += 1
+                    continue
+
+                if empty_cell_counter > 0:
+                    ret += str(empty_cell_counter)
+                    empty_cell_counter = 0
+                letter = piece.letter()
+                ret += letter.lower() if piece.colour == Colour.BLACK else letter.upper()
+
+            if empty_cell_counter > 0:
+                ret += str(empty_cell_counter)
+
+            if y > 0:
+                ret += "/"
+        ret += " "
+
+        ret += "w" if self._turn == Colour.WHITE else "b"
+        ret += " "
+
+        if len(self._white_castling_rights) == 0 and len(self._black_castling_rights) == 0:
+            ret += "-"
+        else: 
+            if CastleSide.King in self._white_castling_rights:
+                ret += "K"
+            if CastleSide.Queen in self._white_castling_rights:
+                ret += "Q"
+
+            if CastleSide.King in self._black_castling_rights:
+                ret += "k"
+            if CastleSide.Queen in self._black_castling_rights:
+                ret += "q"
+        ret += " "
+
+        if self._en_passant_target is not None:
+            pos = Position(self._en_passant_target.pos.x, self._en_passant_target.pos.y)
+            pos.y += -1 if self._en_passant_target.colour == Colour.WHITE else 1
+            ret += pos.to_algebraic()
+        else:
+            ret += "-"
+        ret += " "
+
+        ret += str(self._n_half_moves)
+        ret += " "
+        ret += str(self._n_moves)
+
+        return ret
+
+
+    def legal_moves(self) -> list[Move]:
+        ret = []
+        pieces = self._white if self._turn == Colour.WHITE else self._black
+        for piece in pieces.values():
+            ret += piece.legal_moves(self)
+        return ret
+
+    def is_terminal(self) -> bool:
+        return self.is_stalemate_for(Colour.WHITE) or self.is_stalemate_for(Colour.BLACK) or self.is_checkmate_for(Colour.WHITE) or self.is_checkmate_for(Colour.BLACK)
+
+    def utility(self) -> int:
+        if self.is_stalemate_for(Colour.WHITE) or self.is_stalemate_for(Colour.BLACK):
+            return 0
+
+        if self.is_checkmate_for(Colour.WHITE):
+            return 1
+
+        if self.is_checkmate_for(Colour.BLACK):
+            return -1
+        
+        raise ValueError("Cannot determine the utility of board become it neither checkmate nor stalemate for either players")
+
+_fen_pos = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+INITIAL_BOARD = Board.setup_FEN_position(_fen_pos)

python/src/logic/move.py

@@ -0,0 +1,51 @@
+# from logic.pieces.piece import Piece
+from typing import Type
+from logic.position import Position
+from enum import Enum
+
+class CastleSide(Enum):
+    Neither = ""
+    King = "O-O"
+    Queen = "O-O-O"
+
+class Move:
+    def __init__(self, piece: "Piece", pos: Position,/, is_capturing: bool = False, castle_side: CastleSide = CastleSide.Neither, en_passant: bool = False, becomes_en_passant_target: bool = False, promotes_to: Type["Piece"] = None) -> None:
+        self.piece = piece
+        self.pos = pos
+        self.is_capturing = is_capturing
+        self.castle_side = castle_side
+        self.becomes_en_passant_target = becomes_en_passant_target
+        self.en_passant = en_passant
+        self.promotes_to = promotes_to
+
+    def to_algebraic(self) -> str:
+        raise NotImplementedError("The move can't be translated to algbraic notation, as it was not implemented")
+
+    @staticmethod
+    def from_algebraic(move: str) -> "Move":
+        raise NotImplementedError("The move can't be translated from algbraic notation, as it was not implemented")
+
+    def __str__(self) -> str:
+        if self.castle_side == CastleSide.King:
+            return "O-O"
+        if self.castle_side == CastleSide.Queen:
+            return "O-O-O"
+
+        ret = ""
+        if type(self.piece).__name__ == "Pawn":
+            if self.is_capturing:
+                ret += self.piece.pos.to_algebraic()[0]
+                ret += "x"
+                ret += self.pos.to_algebraic()
+            else:
+                ret += self.pos.to_algebraic()
+        else:
+            ret += self.piece.letter().upper()
+            if self.is_capturing:
+                ret += "x"
+            ret += str(self.pos)
+        
+        return ret
+    
+    def __repr__(self) -> str:
+        return str(self)

python/src/logic/pieces/bishop.py

@@ -0,0 +1,24 @@
+from logic.move import Move
+from .piece import Piece
+
+class Bishop(Piece):
+    def legal_moves(self, board: "Board", / , looking_for_check = False) -> list[Move]:
+        ret = []
+
+        # looking north east
+        ret.extend(self._look_direction(board, 1, 1))
+
+        # looking south east
+        ret.extend(self._look_direction(board, 1, -1))
+
+        # looking south west
+        ret.extend(self._look_direction(board, -1, -1))
+
+        # looking north west
+        ret.extend(self._look_direction(board, -1, 1))
+
+        if not looking_for_check:# and board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        return ret
+

python/src/logic/pieces/king.py

@@ -0,0 +1,69 @@
+from logic.move import CastleSide, Move
+from logic.position import Position
+from .piece import Piece
+
+class King(Piece):
+    def legal_moves(self, board: "Board") -> list[Move]:
+        ret = []
+
+        # -- Regular moves
+        for dx in [-1, 0, 1]:
+            for dy in [-1, 0, 1]:
+                if dx == 0 and dy == 0: # skip current position
+                    continue
+                x = self.pos.x + dx
+                y = self.pos.y + dy
+                move = self._move_for_position(board, x, y)
+                if move:
+                    board_after_move = board.make_move(move)
+                    if not board_after_move.is_check_for(self.colour):
+                        ret.append(move)
+
+        if board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        # -- Castles
+        castling_rights = board.castling_rights_for(self.colour)
+        if len(castling_rights) == 0:
+            return ret
+
+        if CastleSide.King in castling_rights:
+            clear = True
+            for dx in range(1, 3):
+                x = self.pos.x + dx
+                y = self.pos.y
+                if board.piece_at(x, y) is not None:
+                    clear = False
+                    break
+
+                move = self._move_for_position(board, x, y)
+                board_after_move = board.make_move(move)
+                if board_after_move.is_check_for(self.colour):
+                    clear = False
+                    break
+
+            if clear:
+                ret.append(Move(self, Position(6, self.pos.y), castle_side=CastleSide.King))
+
+        if CastleSide.Queen in castling_rights:
+            clear = True
+            for dx in range(1, 4):
+                x = self.pos.x - dx
+                y = self.pos.y
+
+                if board.piece_at(x, y) is not None:
+                    clear = False
+                    break
+
+                move = self._move_for_position(board, x, y)
+                board_after_move = board.make_move(move)
+                if dx < 3 and board_after_move.is_check_for(self.colour):
+                    clear = False
+                    break
+
+            if clear:
+                ret.append(Move(self, Position(2, self.pos.y), castle_side=CastleSide.Queen))
+
+        return ret
+
+

python/src/logic/pieces/knight.py

@@ -0,0 +1,23 @@
+from .piece import Piece
+
+class Knight(Piece):
+    def letter(self):
+        return "n"
+
+    def legal_moves(self, board: "Board", / , looking_for_check = False) -> list["Move"]:
+        ret = []
+        for dx, dy in [
+            (+2, +1), (+1, +2), # north east
+            (+2, -1), (+1, -2), # south east
+            (-2, -1), (-1, -2), # south west
+            (-2, +1), (-1, +2), # north west
+        ]:
+            move = self._move_for_position(board, self.pos.x + dx, self.pos.y + dy)
+            if move is not None:
+                ret.append(move)
+
+        if not looking_for_check:# and board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        return ret
+

python/src/logic/pieces/pawn.py

@@ -0,0 +1,80 @@
+from logic.move import Move
+from logic.pieces.bishop import Bishop
+from logic.pieces.knight import Knight
+from logic.pieces.piece import Colour, Piece
+from logic.pieces.queen import Queen
+from logic.pieces.rook import Rook
+from logic.position import Position
+
+class Pawn(Piece):
+    def legal_moves(self, board, / , looking_for_check = False) -> list[Move]:
+        ret = []
+
+        # can we capture to the left?
+        if self.pos.x > 0 and (
+            (self.colour == Colour.WHITE and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y + 1)))
+            or
+            (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y - 1)))
+        ):
+            if capturable_piece.colour != self.colour:
+                if (self.colour == Colour.WHITE and capturable_piece.pos.y == 7) or (self.colour == Colour.BLACK and capturable_piece.pos.y == 0):
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, capturable_piece.pos, is_capturing=True, promotes_to=piece))
+                else:
+                    ret.append(Move(self, capturable_piece.pos, is_capturing = True))
+
+        # can we capture to the right?
+        if self.pos.x < 7 and (
+            (self.colour == Colour.WHITE and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y + 1)))
+            or
+            (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y - 1)))
+        ):
+            if capturable_piece.colour != self.colour:
+                if (self.colour == Colour.WHITE and capturable_piece.pos.y == 7) or (self.colour == Colour.BLACK and capturable_piece.pos.y == 0):
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, capturable_piece.pos, is_capturing=True, promotes_to=piece))
+                else:
+                    ret.append(Move(self, capturable_piece.pos, is_capturing = True))
+
+        # -- Can we capture en passant?
+        if board._en_passant_target is not None and \
+            board._en_passant_target.pos.y == self.pos.y and (
+                board._en_passant_target.pos.x == self.pos.x - 1
+                or board._en_passant_target.pos.x == self.pos.x + 1
+        ):
+            if board._en_passant_target.colour != self.colour:
+                old_pos = board._en_passant_target.pos
+                new_pos = Position(old_pos.x, old_pos.y + (1 if self.colour == Colour.WHITE else -1))
+                ret.append(Move(self, new_pos, is_capturing = True, en_passant = True))
+
+        # -- Normal moves
+        if self.colour == Colour.WHITE:
+            for dy in range(1, 3 if self.pos.y == 1 else 2):
+                y = self.pos.y + dy
+                if y > 7 or board.piece_at(self.pos.x, y):
+                    break
+                pos = Position(self.pos.x, y)
+                if y == 7:
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, pos, promotes_to=piece))
+                else:
+                    ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
+        else:
+            for dy in range(1, 3 if self.pos.y == 6 else 2):
+                y = self.pos.y - dy
+                if y < 0 or board.piece_at(self.pos.x, y):
+                    break
+                pos = Position(self.pos.x, y)
+                if y == 0:
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, pos, promotes_to=piece))
+                else:
+                    ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
+
+        if not looking_for_check:# and board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        return ret
+
+    def letter(self):
+        return "p"

python/src/logic/pieces/piece.py

@@ -0,0 +1,65 @@
+from logic.move import Move
+from logic.position import Position
+from enum import Enum
+
+
+class Colour(Enum):
+    WHITE = "white"
+    BLACK = "black"
+
+    def __str__(self) -> str:
+        return self.value
+
+class Piece:
+    def __init__(self, pos: Position, colour: Colour) -> None:
+        self.pos = pos
+        assert colour == Colour.WHITE or colour == Colour.BLACK, "The colour of the piece must be either Piece.WHITE or Piece.BLACK"
+        self.colour = colour
+
+    def letter(self):
+        return type(self).__name__[0].lower()
+
+    def keep_only_blocking(self, candidates: list[Move], board: "Board") -> list[Move]:
+        ret = []
+        for move in candidates:
+            board_after_move = board.make_move(move)
+            if not board_after_move.is_check_for(self.colour):
+                ret.append(move)
+        return ret
+
+    def _look_direction(self, board: "Board", mult_dx: int, mult_dy: int):
+        ret = []
+        for d in range(1, 8):
+            dx = mult_dx * d
+            dy = mult_dy * d
+
+            move = self._move_for_position(board, self.pos.x + dx, self.pos.y + dy)
+            if move is None:
+                break
+            ret.append(move)
+            if move.is_capturing:
+                break
+
+        return ret
+
+    def _move_for_position(self, board: "Board", x: int, y: int) -> Move | None:
+        if not Position.is_within_bounds(x, y):
+            return None
+        piece = board.piece_at(x, y) 
+
+        if piece is None:
+            return Move(self, Position(x, y))
+
+        if piece.colour != self.colour:
+            return Move(self, Position(x, y), is_capturing=True)
+        return None
+
+    def position(self) -> Position:
+        return self.pos
+
+    def move_to(self, pos: Position) -> "Piece":
+        ret = type(self)(pos, self.colour)
+        return ret
+
+    def legal_moves(self, board: "Board", / , looking_for_check = False) -> list["Move"]:
+        raise NotImplementedError(f"Can't say what the legal moves are for {type(self).__name__}, the method hasn't been implemented yet")

python/src/logic/pieces/queen.py

@@ -0,0 +1,35 @@
+from logic.move import Move
+from .piece import Piece
+
+class Queen(Piece):
+    def legal_moves(self, board: "Board", / , looking_for_check = False) -> list[Move]:
+        ret = []
+
+        # looking north east
+        ret.extend(self._look_direction(board, 1, 1))
+
+        # looking south east
+        ret.extend(self._look_direction(board, 1, -1))
+
+        # looking south west
+        ret.extend(self._look_direction(board, -1, -1))
+
+        # looking north west
+        ret.extend(self._look_direction(board, -1, 1))
+
+        # looking east
+        ret.extend(self._look_direction(board, 1, 0))
+
+        # looking south
+        ret.extend(self._look_direction(board, 0, -1))
+
+        # looking west
+        ret.extend(self._look_direction(board, -1, 0))
+
+        # looking north
+        ret.extend(self._look_direction(board, 0, 1))
+
+        if not looking_for_check:# and board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        return ret

python/src/logic/pieces/rook.py

@@ -0,0 +1,23 @@
+from logic.move import Move
+from .piece import Piece
+
+class Rook(Piece):
+    def legal_moves(self, board: "Board", / , looking_for_check = False) -> list[Move]:
+        ret = []
+
+        # looking east
+        ret.extend(self._look_direction(board, 1, 0))
+
+        # looking south
+        ret.extend(self._look_direction(board, 0, -1))
+
+        # looking west
+        ret.extend(self._look_direction(board, -1, 0))
+
+        # looking north
+        ret.extend(self._look_direction(board, 0, 1))
+
+        if not looking_for_check:# and board.is_check_for(self.colour):
+            return self.keep_only_blocking(ret, board)
+
+        return ret

python/src/logic/position.py

@@ -0,0 +1,43 @@
+class Position:
+    _RANKS = range(1, 9)
+    _FILES = "abcdefgh"
+
+    _MIN_POS = 0
+    _MAX_POS = 7
+
+    def __init__(self, x, y) -> None:
+        assert x >= self._MIN_POS and x <= self._MAX_POS, f"Invalid argument: x should be between {self._MIN_POS} and {self._MAX_POS}, but is {x}"
+        assert y >= self._MIN_POS and y <= self._MAX_POS, f"Invalid argument: y should be between {self._MIN_POS} and {self._MAX_POS}, but is {y}"
+
+        self.x = x
+        self.y = y
+
+    @staticmethod
+    def is_within_bounds(x: int, y: int) -> bool:
+        return x >= Position._MIN_POS and x <= Position._MAX_POS \
+            and y >= Position._MIN_POS and y <= Position._MAX_POS
+
+    @staticmethod
+    def from_algebraic(square: str) -> "Position":
+        assert len(square) == 2, f"'{square}' is malformed"
+        x = Position._FILES.index(square[0])
+        y = Position._RANKS.index(int(square[1]))
+
+        return Position(x, y)
+
+    def to_algebraic(self) -> str:
+        return f"{Position._FILES[self.x]}{Position._RANKS[self.y]}"
+
+    def __eq__(self, value: object, /) -> bool:
+        if type(value) != type(self):
+            return False
+        return value.x == self.x and value.y == self.y
+
+    def __hash__(self) -> int:
+        return hash((self.x, self.y))
+
+    def __str__(self) -> str:
+        return f"{Position._FILES[self.x]}{Position._RANKS[self.y]}"
+
+    def __repr__(self) -> str:
+        return str(self)