Fix an issue where prettyprint_move would write out moves Chess.js did not want to...

diff --git a/Board.pm b/Board.pm
index 91d1a15f7f42b29d5057c2cb9205ae4874a52361..8573bd8f29814e7cdce82555332b4eda3dc612b0 100644 (file)
--- a/Board.pm
+++ b/Board.pm
@@ -387,6 +387,20 @@ sub can_reach {
        return 0;
 }
 
        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 },
 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 },


@@ -544,7 +558,7 @@ sub _prettyprint_move_no_check_or_mate {
        for my $col (0..7) {
                for my $row (0..7) {
                        next unless ($board->[$row][$col] eq $piece);
        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));

                }
        }
 
                }
        }
 


@@ -552,14 +566,14 @@ sub _prettyprint_move_no_check_or_mate {
        my $num_row = 0;
        for my $col (0..7) {
                next unless ($board->[$from_row][$col] eq $piece);
        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);
        }
 
        # 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
        }
 
        # see if we need to disambiguate