added pawn promotion

src/logic/board.py

@@ -184,6 +184,10 @@ class Board:
             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]

src/logic/move.py

@@ -1,4 +1,5 @@
 # from logic.pieces.piece import Piece
+from typing import Type
 from logic.position import Position
 from enum import Enum
 
@@ -8,13 +9,14 @@ class CastleSide(Enum):
     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) -> None:
+    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")

src/logic/pieces/pawn.py

@@ -1,5 +1,9 @@
 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):
@@ -13,7 +17,11 @@ class Pawn(Piece):
             (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y - 1)))
         ):
             if capturable_piece.colour != self.colour:
-                ret.append(Move(self, capturable_piece.pos, is_capturing = True))
+                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 (
@@ -22,7 +30,11 @@ class Pawn(Piece):
             (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y - 1)))
         ):
             if capturable_piece.colour != self.colour:
-                ret.append(Move(self, capturable_piece.pos, is_capturing = True))
+                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 \
@@ -38,16 +50,26 @@ class Pawn(Piece):
         # -- Normal moves
         if self.colour == Colour.WHITE:
             for dy in range(1, 3 if self.pos.y == 1 else 2):
-                if self.pos.y + dy > 7 or board.piece_at(self.pos.x, self.pos.y + dy):
+                y = self.pos.y + dy
+                if y > 7 or board.piece_at(self.pos.x, y):
                     break
-                pos = Position(self.pos.x, self.pos.y + dy)
+                pos = Position(self.pos.x, y)
-                ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
+                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):
-                if self.pos.y - dy < 0 or board.piece_at(self.pos.x, self.pos.y - dy):
+                y = self.pos.y - dy
+                if y < 0 or board.piece_at(self.pos.x, y):
                     break
-                pos = Position(self.pos.x, self.pos.y - dy)
+                pos = Position(self.pos.x, y)
-                ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
+                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)