def _to_san(self):
if self.is_oo:
san = 'O-O'
elif self.is_ooo:
san = 'O-O-O'
elif self.pc in ['P', 'p']:
san = ''
if self.is_capture or self.is_ep:
san += 'abcdefgh'[file_(self.fr)] + 'x'
san += sq_to_str(self.to)
if self.prom:
san += '=' + self.prom.upper()
else:
assert (not self.is_ep)
san = self.pc.upper()
ambigs = self.pos.get_from_sqs(self.pc, self.to)
assert (len(ambigs) >= 1)
if len(ambigs) > 1:
r = rank(self.fr)
f = file_(self.fr)
# try disambiguating with file
if len(filter(lambda sq: file_(sq) == f, ambigs)) == 1:
san += 'abcdefgh'[f]
elif len(filter(lambda sq: rank(sq) == r, ambigs)) == 1:
san += '12345678'[r]
else:
san += sq_to_str(self.fr)
if self.is_capture:
san += 'x'
san += sq_to_str(self.to)
return san
def __init__(self,
pos,
fr,
to,
prom=None,
is_oo=False,
is_ooo=False,
is_ep=False,
new_ep=None):
self.pos = pos
self.fr = fr
self.to = to
self.pc = self.pos.board[self.fr]
self.prom = prom
self.is_oo = is_oo
self.is_ooo = is_ooo
self.capture = pos.board[to]
self.is_capture = self.capture != '-'
self.is_ep = is_ep
self.new_ep = new_ep
self.time = None
self.clock_time = None
self._san = None
self._verbose_alg = None
self.lag = 0
# if a promotion piece is not given, assume queen
if not self.prom:
if self.pc == 'p' and rank(to) == 0:
self.prom = 'q'
elif self.pc == 'P' and rank(to) == 7:
self.prom = 'Q'
def check_pseudo_legal(self):
"""Tests if a move is pseudo-legal, that is, legal ignoring the
fact that a capture must be made if possible. Also sets en passant
flags for this move. This is used for long algebraic moves,
but not san, which does these checks implicitly."""
if self.pc == '-' or piece_is_white(self.pc) != self.pos.wtm:
raise IllegalMoveError('can only move own pieces')
if self.is_capture and piece_is_white(self.capture) == self.pos.wtm:
raise IllegalMoveError('cannot capture own piece')
diff = self.to - self.fr
if self.pc == 'p':
if self.pos.board[self.to] == '-':
if diff == -0x10:
pass
elif diff == -0x20 and rank(self.fr) == 6:
self.new_ep = self.fr - 0x10
if self.pos.board[self.new_ep] != '-':
raise IllegalMoveError('bad en passant')
elif diff in [-0x11, -0xf] and self.to == self.pos.ep:
self.is_ep = True
else:
raise IllegalMoveError('bad pawn push')
else:
if not diff in [-0x11, -0xf]:
raise IllegalMoveError('bad pawn capture')
elif self.pc == 'P':
if self.pos.board[self.to] == '-':
if diff == 0x10:
pass
elif diff == 0x20 and rank(self.fr) == 1:
self.new_ep = self.fr + 0x10
if self.pos.board[self.new_ep] != '-':
raise IllegalMoveError('bad en passant')
elif diff in [0x11, 0xf] and self.to == self.pos.ep:
self.is_ep = True
else:
raise IllegalMoveError('bad pawn push')
else:
if not diff in [0x11, 0xf]:
raise IllegalMoveError('bad pawn capture')
else:
if self.pc in sliding_pieces:
d = dir(self.fr, self.to)
if d == 0 or not d in piece_moves[self.pc.lower()]:
raise IllegalMoveError('piece cannot make that move')
# now check if there are any pieces in the way
cur_sq = self.fr + d
while cur_sq != self.to:
assert (valid_sq(cur_sq))
if self.pos.board[cur_sq] != '-':
raise IllegalMoveError('sliding piece blocked')
cur_sq += d
else:
if not diff in piece_moves[self.pc.lower()]:
raise IllegalMoveError('piece cannot make that move')
def detect_check(self):
"""detect whether the player to move is out of material
(has committed suicide) or stalemated, or if the game
is drawn by opposite color bishops"""
self.is_suicide = not any(pc != '-' and (
piece_is_white(pc) if self.wtm else not piece_is_white(pc))
for (sq, pc) in self)
self.is_stalemate = not self._any_legal_moves()
if self.is_stalemate:
white_material = sum(piece_material[pc.lower()]
for (sq, pc) in self
if pc != '-' and piece_is_white(pc))
black_material = sum(piece_material[pc.lower()]
for (sq, pc) in self
if pc != '-' and not piece_is_white(pc))
self.is_stalemate_white = white_material < black_material
self.is_stalemate_black = white_material > black_material
self.is_draw_bishops = False
for (sq, pc) in self:
if pc == 'B':
if (rank(sq) ^ file_(sq)) & 1 != 0:
break
elif pc == 'b':
if (rank(sq) ^ file_(sq)) & 1 == 0:
break
elif pc != '-':
break
else:
self.is_draw_bishops = True
return
for (sq, pc) in self:
if pc == 'B':
if (rank(sq) ^ file_(sq)) & 1 == 0:
break
elif pc == 'b':
if (rank(sq) ^ file_(sq)) & 1 != 0:
break
elif pc != '-':
break
else:
self.is_draw_bishops = True
def _any_pc_moves(self, sq, pc):
if pc == 'P':
if self.board[sq + 0x10] == '-':
if Move(self, sq, sq + 0x10).is_legal():
return True
if rank(sq) == 1 and self.board[sq + 0x20] == '-' and Move(
self, sq, sq + 0x20).is_legal():
return True
if self._pawn_cap_at(sq + 0xf) and Move(
self, sq, sq + 0xf, is_ep=sq + 0xf == self.ep).is_legal():
return True
if self._pawn_cap_at(sq + 0x11) and Move(
self, sq, sq + 0x11, is_ep=sq + 0x11
== self.ep).is_legal():
return True
elif pc == 'p':
if self.board[sq - 0x10] == '-':
if Move(self, sq, sq - 0x10).is_legal():
return True
if rank(sq) == 6 and self.board[sq - 0x20] == '-' and Move(
self, sq, sq - 0x20).is_legal():
return True
if self._pawn_cap_at(sq - 0xf) and Move(
self, sq, sq - 0xf, is_ep=sq - 0xf == self.ep).is_legal():
return True
if self._pawn_cap_at(sq - 0x11) and Move(
self, sq, sq - 0x11, is_ep=sq - 0x11
== self.ep).is_legal():
return True
else:
for d in piece_moves[pc.lower()]:
cur_sq = sq + d
# we don't need to check castling because if castling
# is legal, some other king move must be also
while valid_sq(cur_sq):
topc = self.board[cur_sq]
if topc == '-' or piece_is_white(topc) != self.wtm:
mv = Move(self, sq, cur_sq)
if mv.is_legal():
return True
if not pc in sliding_pieces or self.board[cur_sq] != '-':
break
cur_sq += d
def move_from_san(self, s):
s = self.decorator_re.sub('', s)
mv = None
# examples: e4 e8=Q
m = self.san_pawn_push_re.match(s)
if m:
to = str_to_sq(m.group(1))
if self.board[to] != '-':
raise IllegalMoveError('pawn push blocked')
prom = m.group(2)
if prom:
if self.wtm:
prom = m.group(2)
assert (prom == prom.upper())
else:
prom = m.group(2).lower()
new_ep = None
if self.wtm:
fr = to - 0x10
if rank(to) == 3 and self.board[fr] == '-':
new_ep = fr
fr = to - 0x20
if self.board[fr] != 'P':
raise IllegalMoveError('illegal white pawn move')
if prom:
if rank(to) == 7:
mv = Move(self, fr, to, prom=prom)
else:
raise IllegalMoveError('illegal promotion')
else:
mv = Move(self, fr, to, new_ep=new_ep)
else:
fr = to + 0x10
if rank(to) == 4 and self.board[fr] == '-':
new_ep = fr
fr = to + 0x20
if self.board[fr] != 'p':
raise IllegalMoveError('illegal black pawn move')
if prom:
if rank(to) == 0:
mv = Move(self, fr, to, prom=prom)
else:
raise IllegalMoveError('illegal promotion')
else:
mv = Move(self, fr, to, new_ep=new_ep)
# examples: dxe4 dxe8=Q
m = None
if not mv:
m = self.san_pawn_capture_re.match(s)
if m:
to = str_to_sq(m.group(2))
prom = m.group(3)
if prom:
if self.wtm:
assert (prom == prom.upper())
else:
prom = prom.lower()
is_ep = to == self.ep
if is_ep:
assert (self.board[to] == '-')
else:
topc = self.board[to]
if topc == '-' or piece_is_white(topc) == self.wtm:
raise IllegalMoveError('bad pawn capture')
f = 'abcdefgh'.index(m.group(1))
if f == file_(to) - 1:
if self.wtm:
fr = to - 0x11
if self.board[fr] != 'P':
raise IllegalMoveError('bad pawn capture')
else:
fr = to + 0xf
if self.board[fr] != 'p':
raise IllegalMoveError('bad pawn capture')
elif f == file_(to) + 1:
if self.wtm:
fr = to - 0xf
if self.board[fr] != 'P':
raise IllegalMoveError('bad pawn capture')
else:
fr = to + 0x11
if self.board[fr] != 'p':
raise IllegalMoveError('bad pawn capture')
else:
raise IllegalMoveError('bad pawn capture file')
mv = Move(self, fr, to, prom=prom, is_ep=is_ep)
# examples: Nf3 Nxf3 Ng1xf3
m = None
if not mv:
m = self.san_piece_re.match(s)
if m:
to = str_to_sq(m.group(5))
if m.group(4):
# capture
if self.board[to] == '-':
raise IllegalMoveError('capture on blank square')
if piece_is_white(self.board[to]) == self.wtm:
raise IllegalMoveError('capture own piece')
else:
if self.board[to] != '-':
raise IllegalMoveError('missing "x" to indicate capture')
pc = m.group(1) if self.wtm else m.group(1).lower()
# TODO: it would be faster to disambiguate first, so we
# do not check whether moves are legal unnecessarily
froms = self.get_from_sqs(pc, to)
if m.group(2):
if len(froms) <= 1:
raise IllegalMoveError('unnecessary disambiguation')
f = 'abcdefgh'.index(m.group(2))
froms = filter(lambda sq: file_(sq) == f, froms)
if m.group(3):
r = '12345678'.index(m.group(3))
if len(froms) <= 1:
raise IllegalMoveError('unnecessary disambiguation')
froms = filter(lambda sq: rank(sq) == r, froms)
if len(froms) != 1:
raise IllegalMoveError(
'illegal or ambiguous move %s: %d interpretations' %
(s, len(froms)))
mv = Move(self, froms[0], to)
# Legality checking is implicitly done above, so we don't need
# to check it here.
'''if mv:
try:
mv.check_pseudo_legal()
except IllegalMoveError:
raise RuntimeError('san inconsistency')
mv.check_legal()'''
return mv
def sq_to_str(sq):
return 'abcdefgh'[file_(sq)] + '12345678'[rank(sq)]
def set_pos(self, fen, detect_check=True):
"""Set the position from Forsyth-Fdwards notation. The format
is intentionally interpreted strictly; better to give the user an
error than take in bad data."""
try:
# rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
m = self.set_pos_re.match(fen)
if not m:
raise BadFenError('does not look like FEN')
(pos, side, castle_flags, ep, fifty_count,
full_moves) = [m.group(i) for i in range(1, 7)]
ranks = pos.split('/')
ranks.reverse()
self.hash = 0
self.material = [0, 0]
for (r, rank_str) in enumerate(ranks):
sq = 0x10 * r
for c in rank_str:
d = '12345678'.find(c)
if d >= 0:
sq += d + 1
else:
assert (valid_sq(sq))
self.board[sq] = c
self.hash ^= zobrist.piece_hash(sq, c)
self.material[piece_is_white(c)] += \
piece_material[c.lower()]
if c == 'k':
if self.king_pos[0] is not None:
# multiple kings
raise BadFenError()
self.king_pos[0] = sq
elif c == 'K':
if self.king_pos[1] is not None:
# multiple kings
raise BadFenError()
self.king_pos[1] = sq
elif c.lower() == 'p':
if rank(sq) in [0, 7]:
# pawn on 1st or 8th rank
raise BadFenError()
sq += 1
if sq & 0xf != 8:
# wrong row length
raise BadFenError()
if None in self.king_pos:
# missing king
raise BadFenError()
self.wtm = side == 'w'
if self.wtm:
self.hash ^= zobrist.side_hash
if castle_flags == '-':
self.castle_flags = 0
else:
(w_oo, w_ooo, b_oo, b_ooo) = (False, False, False, False)
for c in castle_flags:
if c == 'K':
if self.board[E1] != 'K' or self.board[H1] != 'R':
raise BadFenError()
if w_oo:
raise BadFenError()
w_oo = True
elif c == 'Q':
if self.board[E1] != 'K' or self.board[A1] != 'R':
raise BadFenError()
if w_ooo:
raise BadFenError()
w_ooo = True
elif c == 'k':
if self.board[E8] != 'k' or self.board[H8] != 'r':
raise BadFenError()
if b_oo:
raise BadFenError()
b_oo = True
elif c == 'q':
if self.board[E8] != 'k' or self.board[A8] != 'r':
raise BadFenError()
if b_ooo:
raise BadFenError()
b_ooo = True
self.castle_flags = to_castle_flags(w_oo, w_ooo, b_oo, b_ooo)
self.hash ^= zobrist.castle_hash(self.castle_flags)
self.fifty_count = int(fifty_count, 10)
self.ply = 2 * (int(full_moves, 10) - 1) + int(not self.wtm)
self.start_ply = self.ply # 0 for new games
if ep == '-':
self.ep = None
else:
# only set ep if there is a legal capture
# XXX: this is even stricter than X-FEN; maybe
# we should not check for true legality, but only
# whether there is an enemy pawn on an adjacent
# square?
self.ep = 'abcdefgh'.index(ep[0]) + \
0x10 * '1234567'.index(ep[1])
if rank(self.ep) not in (2, 5):
raise BadFenError('bad en passant square')
self.hash ^= zobrist.ep_hash(self.ep)
# legality checking needs a value for in_check
self.in_check = None
if not self._is_legal_ep(self.ep):
# undo the en passant square
self.ep = None
self.hash ^= zobrist.ep_hash(self.ep)
#assert(self.hash == self._compute_hash())
self.history.set_hash(self.ply, self.hash)
if detect_check:
self.detect_check()
if self.is_checkmate or self.is_stalemate \
or self.is_draw_nomaterial:
raise BadFenError('got a terminal position')
except AssertionError:
raise
def set_pos(self, fen):
"""Set the position from Forsyth-Fdwards notation. The format
is intentionally interpreted strictly; better to give the user an
error than take in bad data."""
try:
# rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1
m = self.set_pos_re.match(fen)
if not m:
raise BadFenError('does not look like FEN')
(pos, side, castle_flags, ep, fifty_count,
full_moves) = [m.group(i) for i in range(1, 7)]
ranks = pos.split('/')
ranks.reverse()
self.hash = 0
self.material = [0, 0]
for (r, rank_str) in enumerate(ranks):
sq = 0x10 * r
for c in rank_str:
d = '12345678'.find(c)
if d >= 0:
sq += d + 1
else:
assert (valid_sq(sq))
self.board[sq] = c
self.hash ^= zobrist.piece_hash(sq, c)
self.material[piece_is_white(c)] += \
piece_material[c.lower()]
if c.lower() == 'p':
if rank(sq) in [0, 7]:
# pawn on 1st or 8th rank
raise BadFenError()
sq += 1
if sq & 0xf != 8:
# wrong row length
raise BadFenError()
self.wtm = side == 'w'
if self.wtm:
self.hash ^= zobrist.side_hash
self.fifty_count = int(fifty_count, 10)
self.ply = 2 * (int(full_moves, 10) - 1) + int(not self.wtm)
self.start_ply = self.ply # 0 for new games
if ep == '-':
self.ep = None
else:
# only set ep if there is a legal capture
# XXX: this is even stricter than X-FEN; maybe
# we should not check for true legality, but only
# whether there is an enemy pawn on an adjacent
# square?
self.ep = 'abcdefgh'.index(ep[0]) + \
0x10 * '1234567'.index(ep[1])
if rank(self.ep) not in (2, 5):
raise BadFenError('bad en passant square')
self.hash ^= zobrist.ep_hash(self.ep)
#assert(self.hash == self._compute_hash())
self.history.set_hash(self.ply, self.hash)
except AssertionError:
raise