Refactored possible_moves method
Tibor Bizjak
parent
6d1f9d06dc
commit
0b16fabcd8
116
chess.py
116
chess.py
|
|
@ -4,6 +4,9 @@ from unicodedata import lookup
|
|||
def cross(A, B):
|
||||
return tuple(a+b for a in A for b in B)
|
||||
|
||||
pieces = ["pawn", "knight", "bishop", "rook", "queen", "king"]
|
||||
colors = ["white", "black"]
|
||||
|
||||
ranks = "87654321"
|
||||
files = "abcdefgh"
|
||||
squares = cross(files, ranks)
|
||||
|
|
@ -18,14 +21,17 @@ init_positions = {"pawn" : cross(files, pawn_ranks),
|
|||
"king" : cross("e", home_ranks)
|
||||
}
|
||||
|
||||
def addv(sq, v):
|
||||
def move(sq, v):
|
||||
return chr(ord(sq[0]) + v[0]) + str(int(sq[1]) + v[1])
|
||||
|
||||
def addvs(sq, vectors):
|
||||
return [addv(sq, v) for v in vectors]
|
||||
up, down = (0, 1), (0, -1)
|
||||
left, right = (-1, 0), (1, 0)
|
||||
rook_dirs = (up, down, left, right)
|
||||
|
||||
def negatevs(vectors):
|
||||
return [(-a, -b) for a,b in vectors]
|
||||
up_left, up_right = (-1, 1), (1, 1)
|
||||
down_left, down_right = (-1, -1), (1, -1)
|
||||
bishop_dirs = (up_left, up_right,
|
||||
down_left, down_right)
|
||||
|
||||
class Piece:
|
||||
def __init__(self, color=None, piece=None):
|
||||
|
|
@ -107,77 +113,73 @@ class Game:
|
|||
return False
|
||||
|
||||
def possible_moves(self, sq):
|
||||
def is_possible(target):
|
||||
return target in squares and \
|
||||
self.board[target].color != self.board[sq].color
|
||||
def are_possible(vecs):
|
||||
r = []
|
||||
sqrs = addvs(sq, vecs)
|
||||
for s in sqrs:
|
||||
if not is_possible(s):
|
||||
break
|
||||
r.append(s)
|
||||
if not self.is_empty(s):
|
||||
break
|
||||
return r
|
||||
|
||||
def possible_rook():
|
||||
rvecs = list(zip(range(1,8), [0]*7))
|
||||
fvecs = [(b,a) for a,b in rvecs]
|
||||
vecs = [rvecs, fvecs, negatevs(rvecs), negatevs(fvecs)]
|
||||
return sum(map(are_possible, vecs), [])
|
||||
|
||||
def possible_bishop():
|
||||
ldvecs = list(zip(range(1,8), range(1,8)))
|
||||
rdvecs = list(zip(range(1,8), range(-1, -8, -1)))
|
||||
vecs = [ldvecs, rdvecs, negatevs(ldvecs), negatevs(rdvecs)]
|
||||
return sum(map(are_possible, vecs), [])
|
||||
if sq not in squares:
|
||||
return []
|
||||
|
||||
board = self.board
|
||||
piece = board[sq].piece
|
||||
color = board[sq].color
|
||||
|
||||
def can_eat(target):
|
||||
if target not in board:
|
||||
return False
|
||||
eaten = board[target]
|
||||
return eaten != None and color != eaten.color
|
||||
|
||||
def can_move_to(sq):
|
||||
return sq in board and self.is_empty(sq)
|
||||
|
||||
def possible_line(dir):
|
||||
target = move(sq, dir)
|
||||
while can_move_to(target):
|
||||
yield target
|
||||
target = move(target, dir)
|
||||
if can_eat(target):
|
||||
yield target
|
||||
|
||||
def possible_lines(dirs):
|
||||
return sum(list(map(list, map(possible_line, dirs))), [])
|
||||
|
||||
rook = possible_lines(rook_dirs)
|
||||
bishop = possible_lines(bishop_dirs)
|
||||
|
||||
if piece == "pawn":
|
||||
r = []
|
||||
direction = (0,1)
|
||||
dir = up
|
||||
if color == "black":
|
||||
direction = (0, -1)
|
||||
frwd = addv(sq, direction)
|
||||
jump = addv(frwd, direction)
|
||||
eatl = addv(frwd, (-1, 0))
|
||||
eatr = addv(frwd, (1, 0))
|
||||
dir = down
|
||||
frwd = move(sq, dir)
|
||||
jump = move(frwd, dir)
|
||||
eat = (move(frwd, left),
|
||||
move(frwd, right))
|
||||
|
||||
if is_possible(frwd) and self.is_empty(frwd):
|
||||
if can_move_to(frwd):
|
||||
r.append(frwd)
|
||||
checklr = lambda x: is_possible(x) \
|
||||
and \
|
||||
not self.is_empty(x) \
|
||||
and \
|
||||
board[x].color != color
|
||||
if checklr(eatl):
|
||||
r.append(eatl)
|
||||
if checklr(eatr):
|
||||
r.append(eatr)
|
||||
is_on_pawn_rank = (color == "black" and sq[1]=='7') \
|
||||
or \
|
||||
(color == "white" and sq[1]=='2')
|
||||
if is_possible(jump) and frwd in r and self.is_empty(jump) and is_on_pawn_rank:
|
||||
if can_move_to(jump) and is_on_pawn_rank:
|
||||
r.append(jump)
|
||||
return r
|
||||
return r + [sq for sq in eat if can_eat(sq)]
|
||||
|
||||
elif piece == "knight":
|
||||
vecs = list(product((1,-1), (2,-2)))
|
||||
vecs += list(product((2,-2), (1,-1)))
|
||||
return [sq for sq in addvs(sq, vecs) if is_possible(sq)]
|
||||
nums = [2, -2, 1, -1]
|
||||
vectors = [(a, b) for a,b in product(nums, nums)
|
||||
if abs(a) != abs(b)]
|
||||
targets = [move(sq, v) for v in vectors]
|
||||
return [sq for sq in targets
|
||||
if can_move_to(sq) or can_eat(sq)]
|
||||
elif piece == "rook":
|
||||
return possible_rook()
|
||||
return rook
|
||||
elif piece == "bishop":
|
||||
return possible_bishop()
|
||||
return bishop
|
||||
elif piece == "queen":
|
||||
return possible_bishop() + possible_rook()
|
||||
return rook + bishop
|
||||
elif piece == "king":
|
||||
vecs = product([-1, 0, 1], [-1, 0, 1])
|
||||
return [sq for sq in addvs(sq, vecs)
|
||||
if is_possible(sq) and not self.is_attacked(sq)]
|
||||
vectors = rook_dirs + bishop_dirs
|
||||
targets = [move[sq, v] for v in vectors]
|
||||
return [sq for sq in targets
|
||||
if can_move_to(sq) and not is_attacked(sq)]
|
||||
return []
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue