Allow O1 as Betza castling descriptor

The notation On is now also recognized as castling for n=1, but this
uses the same system as non-royal castling ('guarding'), which is
performed as hit-and-run capture of the Rook (or whatever you want to
castle with) while moving to the destination (one square away here).
This to avoid the ambiguity with normal King moves (which for the
guarding always existed).

diff --git a/moves.c b/moves.c
index 68bf107..f00e712 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -286,7 +286,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
     if(pc == WhitePawn || pc == WhiteLance) promo = WhitePromotion, promoRank = BOARD_HEIGHT-1; else
     if(pc == BlackPawn || pc == BlackLance) promo = BlackPromotion, promoRank = 0;
     while(*p) {                  // more moves to go
-       int expo = 1, dx, dy, x, y, mode, dirSet, ds2=0, retry=0, initial=0, jump=1, skip = 0, all = 0;
+       int expo = -1, dx, dy, x, y, mode, dirSet, ds2=0, retry=0, initial=0, jump=1, skip = 0, all = 0;
        char *cont = NULL;
        while(*p == 'i') initial++, desc = ++p;
        while(islower(*p)) p++;  // skip prefixes
@@ -377,9 +377,10 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
        if(initial && (board[r][f] != initialPosition[r][f] ||
                       r == 0              && board[TOUCHED_W] & 1<<f ||
                       r == BOARD_HEIGHT-1 && board[TOUCHED_B] & 1<<f   ) ) continue;
-       if(expo > 1 && dx == 0 && dy == 0) {          // castling indicated by O + number
+       if(expo > 0 && dx == 0 && dy == 0) {          // castling indicated by O + number
            mode |= 1024; dy = 1;
        }
+       if(expo < 0) expo = 1;                        // use 1 for default
         if(!cont) {
            if(!(mode & 15)) mode |= his + 4;         // no mode spec, use default = mc
        } else {
@@ -450,7 +451,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
                    if(occup == 4) continue; // skip empty squares
                    if((x == BOARD_LEFT + skip || x > BOARD_LEFT + skip && vx < 0 && board[y][x-1-skip] == DarkSquare)
                                                                    && board[y][x] == initialPosition[y][x]) { // reached initial corner piece
-                     if(pc != WhiteKing && pc != BlackKing) { // non-royal castling (to be entered as two-leg move via 'Rook')
+                     if(pc != WhiteKing && pc != BlackKing || expo == 1) { // non-royal castling (to be entered as two-leg move via 'Rook')
                        if(killX < 0) cb(board, flags, FirstLeg,   r, f, y, x, cl); if(killX < f)
                        legNr <<= 1,  cb(board, flags, NormalMove, r, f, y, f - expo, cl), legNr >>= 1;
                      } else
@@ -458,7 +459,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
                    }
                    if((x == BOARD_RGHT-1-skip || x < BOARD_RGHT-1-skip && vx > 0 && board[y][x+1+skip] == DarkSquare)
                                                                    && board[y][x] == initialPosition[y][x]) {
-                     if(pc != WhiteKing && pc != BlackKing) {
+                     if(pc != WhiteKing && pc != BlackKing || expo == 1) {
                        if(killX < 0) cb(board, flags, FirstLeg,   r, f, y, x, cl); if(killX > f)
                        legNr <<= 1,  cb(board, flags, NormalMove, r, f, y, f + expo, cl), legNr >>= 1;
                      } else