return _pos_to_square($from_row, $from_col) . _pos_to_square($to_row, $to_col) . $promo;
}
+# Note: This is in general not a validation that the move is actually allowed
+# (e.g. you can castle even though you're in check).
sub parse_pretty_move {
my ($board, $move, $toplay) = @_;
}
$move =~ /^([KQRBN])?([a-h])?([1-8])?x?([a-h][1-8])$/ or die "Invalid move $move";
- my $piece = $1 // 'P';
+ my $piece = $1;
my $from_col = defined($2) ? _col_letter_to_num($2) : undef;
my $from_row = defined($3) ? _row_letter_to_num($3) : undef;
+ if (!defined($piece) && (!defined($from_col) || !defined($from_row))) {
+ $piece = 'P';
+ }
my ($to_row, $to_col) = _square_to_pos($4);
# Find all possible from-squares that could have been meant.
my @squares = ();
my $side = 'K';
if ($toplay eq 'B') {
- $piece = lc($piece);
+ $piece = lc($piece) if defined($piece);
$side = 'k';
}
for my $row (0..7) {
next if (defined($from_row) && $from_row != $row);
for my $col (0..7) {
next if (defined($from_col) && $from_col != $col);
- next if ($board->[$row][$col] ne $piece);
- next if (!$board->can_reach($piece, $row, $col, $to_row, $to_col));
-
- # See if doing this move would put us in check
- # (yes, there are clients that expect us to do this).
- next if ($board->make_move($row, $col, $to_row, $to_col, $promo)->in_check($side));
+ next if (defined($piece) && $board->[$row][$col] ne $piece);
push @squares, [ $row, $col ];
}
}
+
+ # Filter out pieces which cannot reach this square.
+ @squares = grep { $board->can_reach($piece, $_->[0], $_->[1], $to_row, $to_col) } @squares;
+
+ # See if doing this move would put us in check
+ # (yes, there are clients that expect us to do this).
+ @squares = grep { !$board->make_move($_->[0], $_->[1], $to_row, $to_col, $promo)->in_check($side) } @squares;
+
if (scalar @squares == 0) {
die "Impossible move $move";
}
return join('/', @rows);
}
+# Returns a compact bit string describing the same data as fen().
+# This is encoded using a Huffman-like encoding, and should be
+# typically about 1/3 the number of bytes.
+sub bitpacked_fen {
+ my ($board) = @_;
+ my $bits = "";
+
+ for my $row (0..7) {
+ for my $col (0..7) {
+ my $piece = $board->[$row][$col];
+ if ($piece eq '-') {
+ $bits .= "0";
+ next;
+ }
+
+ my $color = (lc($piece) eq $piece) ? 0 : 1;
+ $bits .= "1" . $color;
+
+ if (lc($piece) eq 'p') {
+ $bits .= "0";
+ } elsif (lc($piece) eq 'n') {
+ $bits .= "100";
+ } elsif (lc($piece) eq 'b') {
+ $bits .= "101";
+ } elsif (lc($piece) eq 'r') {
+ $bits .= "1110";
+ } elsif (lc($piece) eq 'q') {
+ $bits .= "11110";
+ } elsif (lc($piece) eq 'k') {
+ $bits .= "11111";
+ } else {
+ die "Unknown piece $piece";
+ }
+ }
+ }
+
+ return pack('b*', $bits);
+}
+
sub can_reach {
my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
return 0;
}
+# Like can_reach, but also checks the move doesn't put the side in check.
+# We use this in prettyprint_move to reduce the disambiguation, because Chess.js
+# needs moves to be in minimally disambiguated form.
+sub can_legally_reach {
+ my ($board, $piece, $from_row, $from_col, $to_row, $to_col) = @_;
+
+ return 0 if (!can_reach($board, $piece, $from_row, $from_col, $to_row, $to_col));
+
+ my $nb = $board->make_move($from_row, $from_col, $to_row, $to_col);
+ my $side = ($piece eq lc($piece)) ? 'k' : 'K';
+
+ return !in_check($nb, $side);
+}
+
my %pieces_against_side = (
k => { K => 1, Q => 1, R => 1, N => 1, B => 1, P => 1 },
K => { k => 1, q => 1, r => 1, n => 1, b => 1, p => 1 },
# white short castling
if ($move eq 'e1g1' && $piece eq 'K') {
- return '0-0';
+ return 'O-O';
}
# white long castling
if ($move eq 'e1c1' && $piece eq 'K') {
- return '0-0-0';
+ return 'O-O-O';
}
# black short castling
if ($move eq 'e8g8' && $piece eq 'k') {
- return '0-0';
+ return 'O-O';
}
# black long castling
if ($move eq 'e8c8' && $piece eq 'k') {
- return '0-0-0';
+ return 'O-O-O';
}
my $pretty;
$pretty = substr($move, 0, 1) . 'x' . _pos_to_square($to_row, $to_col);
} else {
$pretty = _pos_to_square($to_row, $to_col);
+ }
- if (defined($promo) && $promo ne '') {
- # promotion
- $pretty .= "=";
- $pretty .= uc($promo);
- }
+ if (defined($promo) && $promo ne '') {
+ # promotion
+ $pretty .= "=";
+ $pretty .= uc($promo);
}
return $pretty;
}
for my $col (0..7) {
for my $row (0..7) {
next unless ($board->[$row][$col] eq $piece);
- ++$num_total if ($board->can_reach($piece, $row, $col, $to_row, $to_col));
+ ++$num_total if ($board->can_legally_reach($piece, $row, $col, $to_row, $to_col));
}
}
my $num_row = 0;
for my $col (0..7) {
next unless ($board->[$from_row][$col] eq $piece);
- ++$num_row if ($board->can_reach($piece, $from_row, $col, $to_row, $to_col));
+ ++$num_row if ($board->can_legally_reach($piece, $from_row, $col, $to_row, $to_col));
}
# and same for columns
my $num_col = 0;
for my $row (0..7) {
next unless ($board->[$row][$from_col] eq $piece);
- ++$num_col if ($board->can_reach($piece, $row, $from_col, $to_row, $to_col));
+ ++$num_col if ($board->can_legally_reach($piece, $row, $from_col, $to_row, $to_col));
}
# see if we need to disambiguate
projects / remoteglot / blobdiff