chess2.py

import pprint, math

pp = pprint.PrettyPrinter()

class Piece:
    def __init__(self, color):
        self.color = color

    def __repr__(self):
        color_str_from_bool = {
            False: 'w',
            True: 'b'
        }

        return self.letter + ' (' + color_str_from_bool[self.color] + ')'

class Pawn(Piece):
    letter = '-'

class King(Piece):
    letter = 'K'

class Queen(Piece):
    letter = 'Q'


class Rook(Piece):
    letter = 'R'

class Knight(Piece):
    letter = 'N'

class Bishop(Piece):
    letter = 'B'

piece_classes = [Pawn, King, Queen, Rook, Knight, Bishop]
piece_from_letter = {}
for piece_class in piece_classes:
    piece_from_letter[piece_class.letter] = piece_class

class Board:
    N = 8
    initial_chessboard = \
"""R]N]B]Q]K]B]N]R]
   -]-]-]-]-]-]-]-]




   -[-[-[-[-[-[-[-[
   R[N[B[Q[K[B[N[R["""

    def __init__(self):
        self.chessboard = []
        for _ in range(Board.N):
            row = []
            for _ in range(Board.N):
                row.append(None)
            self.chessboard.append(row)

    def initialize_positions(self):
        lines = Board.initial_chessboard.splitlines()
        stripped_lines = []
        for line in lines:
            stripped_lines.append(line.strip())
        for row, line in enumerate(stripped_lines):
            for i in range(0, len(line), 2):
                piece_type = line[i]
                piece_color = line[i + 1]
                piece_class = piece_from_letter[piece_type]
                assert(piece_color in ('[', ']'))
                color = piece_color == ']'
                piece = piece_class(color)
                self.chessboard[row][i//2] = piece

    def available_moves(self, row, col):
        moves = []
        piece = self.chessboard[row][col]
        if piece is None:
            return []
        print(piece.letter)
        for candidate_row, line in enumerate(self.chessboard):
            for candidate_col, current_piece in enumerate(line):
                if self.chessboard[candidate_row][candidate_col] is None:
                    if abs(candidate_row - row) == abs(candidate_col - col):
                        moves.append((candidate_row, candidate_col))
        return moves

board = Board()
board.initialize_positions()
moves = board.available_moves(7, 5)
print(moves)