my $nb = [];
for my $row (0..7) {
- for my $col (0..7) {
- $nb->[$row][$col] = $board->[$row][$col];
- }
+ $nb->[$row] = [ @{$board->[$row]} ];
}
return bless $nb;
# Returns a new board.
sub make_move {
my ($board, $from_row, $from_col, $to_row, $to_col, $promo) = @_;
- my $move = _move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
+ my $move = move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
my $piece = $board->[$from_row][$from_col];
my $nb = $board->clone();
# en passant?
if ($board->[$to_row][$to_col] eq '-') {
if ($piece eq 'p') {
- $nb->[$to_row + 1][$to_col] = '-';
- } else {
$nb->[$to_row - 1][$to_col] = '-';
- }
- }
- } else {
- if (defined($promo) && $promo ne '') {
- if ($piece eq 'p') {
- $piece = $promo;
} else {
- $piece = uc($promo);
+ $nb->[$to_row + 1][$to_col] = '-';
}
}
}
+ if (defined($promo) && $promo ne '') {
+ if ($piece eq 'p') {
+ $piece = lc($promo);
+ } else {
+ $piece = uc($promo);
+ }
+ }
}
# update the board
return (_row_letter_to_num($2), _col_letter_to_num($1));
}
-sub _move_to_uci_notation {
+sub move_to_uci_notation {
my ($from_row, $from_col, $to_row, $to_col, $promo) = @_;
$promo //= "";
return _pos_to_square($from_row, $from_col) . _pos_to_square($to_row, $to_col) . $promo;
# Find all possible from-squares that could have been meant.
my @squares = ();
+ my $side = 'K';
if ($toplay eq 'B') {
$piece = lc($piece);
+ $side = 'k';
}
for my $row (0..7) {
next if (defined($from_row) && $from_row != $row);
# See if doing this move would put us in check
# (yes, there are clients that expect us to do this).
- my $check = $board->make_move($row, $col, $to_row, $to_col, $promo)->in_check();
- next if ($check eq 'both' ||
- ($toplay eq 'W' && $check eq 'white') ||
- ($toplay eq 'B' && $check eq 'black'));
-
+ next if ($board->make_move($row, $col, $to_row, $to_col, $promo)->in_check($side));
push @squares, [ $row, $col ];
}
}
if ($dest_piece ne '-') {
return 0 if (($piece eq lc($piece)) == ($dest_piece eq lc($dest_piece)));
}
-
- if (lc($piece) eq 'k') {
- return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
+
+ if ($piece eq 'p') {
+ # black pawn
+ if ($to_col == $from_col && $to_row == $from_row + 1) {
+ return ($dest_piece eq '-');
+ }
+ if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
+ my $middle_piece = $board->[2][$to_col];
+ return ($dest_piece eq '-' && $middle_piece eq '-');
+ }
+ if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
+ if ($dest_piece eq '-') {
+ # En passant. TODO: check that the last move was indeed an EP move
+ return ($to_row == 5 && $board->[4][$to_col] eq 'P');
+ } else {
+ return 1;
+ }
+ }
+ return 0;
}
+ if ($piece eq 'P') {
+ # white pawn
+ if ($to_col == $from_col && $to_row == $from_row - 1) {
+ return ($dest_piece eq '-');
+ }
+ if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
+ my $middle_piece = $board->[5][$to_col];
+ return ($dest_piece eq '-' && $middle_piece eq '-');
+ }
+ if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
+ if ($dest_piece eq '-') {
+ # En passant. TODO: check that the last move was indeed an EP move
+ return ($to_row == 2 && $board->[3][$to_col] eq 'p');
+ } else {
+ return 1;
+ }
+ }
+ return 0;
+ }
+
if (lc($piece) eq 'r') {
return 0 unless ($from_row == $to_row || $from_col == $to_col);
return (can_reach($board, 'R', $from_row, $from_col, $to_row, $to_col) ||
can_reach($board, 'B', $from_row, $from_col, $to_row, $to_col));
}
-
- # TODO: en passant
- if ($piece eq 'p') {
- # black pawn
- if ($to_col == $from_col && $to_row == $from_row + 1) {
- return ($dest_piece eq '-');
- }
- if ($to_col == $from_col && $from_row == 1 && $to_row == 3) {
- my $middle_piece = $board->[2][$to_col];
- return ($dest_piece eq '-' && $middle_piece eq '-');
- }
- if (abs($to_col - $from_col) == 1 && $to_row == $from_row + 1) {
- return ($dest_piece ne '-');
- }
- return 0;
- }
- if ($piece eq 'P') {
- # white pawn
- if ($to_col == $from_col && $to_row == $from_row - 1) {
- return ($dest_piece eq '-');
- }
- if ($to_col == $from_col && $from_row == 6 && $to_row == 4) {
- my $middle_piece = $board->[5][$to_col];
- return ($dest_piece eq '-' && $middle_piece eq '-');
- }
- if (abs($to_col - $from_col) == 1 && $to_row == $from_row - 1) {
- return ($dest_piece ne '-');
- }
- return 0;
+ if (lc($piece) eq 'k') {
+ return (abs($from_row - $to_row) <= 1 && abs($from_col - $to_col) <= 1);
}
-
+
# unknown piece
return 0;
}
-# Returns 'none', 'white', 'black' or 'both', depending on which sides are in check.
-# The latter naturally indicates an invalid position.
-sub in_check {
- my $board = shift;
- my ($black_check, $white_check) = (0, 0);
+my %pieces_against_side = (
+ k => { K => 1, Q => 1, R => 1, N => 1, B => 1, P => 1 },
+ K => { k => 1, q => 1, r => 1, n => 1, b => 1, p => 1 },
+);
- my ($wkr, $wkc, $bkr, $bkc) = _find_kings($board);
+# Returns whether the given side (given as k or K for black and white) is in check.
+sub in_check {
+ my ($board, $side) = @_;
+ my ($kr, $kc) = _find_piece($board, $side);
- # check all pieces for the possibility of threatening the two kings
+ # check all pieces for the possibility of threatening this king
for my $row (0..7) {
+ next unless grep { exists($pieces_against_side{$side}{$_}) } @{$board->[$row]};
for my $col (0..7) {
my $piece = $board->[$row][$col];
next if ($piece eq '-');
-
- if (uc($piece) eq $piece) {
- # white piece
- $black_check = 1 if ($board->can_reach($piece, $row, $col, $bkr, $bkc));
- } else {
- # black piece
- $white_check = 1 if ($board->can_reach($piece, $row, $col, $wkr, $wkc));
- }
+ return 1 if ($board->can_reach($piece, $row, $col, $kr, $kc));
}
}
- if ($black_check && $white_check) {
- return 'both';
- } elsif ($black_check) {
- return 'black';
- } elsif ($white_check) {
- return 'white';
- } else {
- return 'none';
- }
+ return 0;
}
-sub _find_kings {
- my $board = shift;
- my ($wkr, $wkc, $bkr, $bkc);
+sub _find_piece {
+ my ($board, $piece) = @_;
for my $row (0..7) {
+ next unless grep { $_ eq $piece } @{$board->[$row]};
for my $col (0..7) {
- my $piece = $board->[$row][$col];
- if ($piece eq 'K') {
- ($wkr, $wkc) = ($row, $col);
- } elsif ($piece eq 'k') {
- ($bkr, $bkc) = ($row, $col);
+ if ($board->[$row][$col] eq $piece) {
+ return ($row, $col);
}
}
}
- return ($wkr, $wkc, $bkr, $bkc);
+ return (undef, undef);
}
-# Returns if any side is in mate.
+# Returns if the given side (given as k or K) is in mate.
sub in_mate {
- my $board = shift;
- my $check = $board->in_check();
- return 0 if ($check eq 'none');
+ my ($board, $side, $in_check) = @_;
+ return 0 if (!$in_check);
# try all possible moves for the side in check
for my $row (0..7) {
my $piece = $board->[$row][$col];
next if ($piece eq '-');
- if ($check eq 'white') {
+ if ($side eq 'K') {
next if ($piece eq lc($piece));
} else {
next if ($piece eq uc($piece));
next if ($row == $dest_row && $col == $dest_col);
next unless ($board->can_reach($piece, $row, $col, $dest_row, $dest_col));
- my $nb = $board->clone();
- $nb->[$row][$col] = '-';
- $nb->[$dest_row][$dest_col] = $piece;
- my $new_check = $nb->in_check();
- return 0 if ($new_check ne $check && $new_check ne 'both');
+ my $nb = $board->make_move($row, $col, $dest_row, $dest_col);
+ return 0 if (!$nb->in_check($side));
}
}
}
my $pretty = $board->_prettyprint_move_no_check_or_mate($from_row, $from_col, $to_row, $to_col, $promo);
my $nb = $board->make_move($from_row, $from_col, $to_row, $to_col, $promo);
- if ($nb->in_mate()) {
+
+ my $piece = $board->[$from_row][$from_col];
+ my $other_side = (uc($piece) eq $piece) ? 'k' : 'K';
+ my $in_check = $nb->in_check($other_side);
+ if ($nb->in_mate($other_side, $in_check)) {
$pretty .= '#';
- } elsif ($nb->in_check() ne 'none') {
+ } elsif ($in_check) {
$pretty .= '+';
}
return ($pretty, $nb);
sub _prettyprint_move_no_check_or_mate {
my ($board, $from_row, $from_col, $to_row, $to_col, $promo) = @_;
my $piece = $board->[$from_row][$from_col];
- my $move = _move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
+ my $move = move_to_uci_notation($from_row, $from_col, $to_row, $to_col, $promo);
if ($piece eq '-') {
die "Invalid move $move";
projects / remoteglot / blobdiff