Implement Betza j on W,F as skip first square

diff --git a/moves.c b/moves.c
index e1b0145..eb2e42e 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -248,7 +248,7 @@ MovesFromString (Board board, int flags, int f, int r, char *desc, MoveCallback
     int mine, his, dir, bit, occup, i;
     if(flags & F_WHITE_ON_MOVE) his = 2, mine = 1; else his = 1, mine = 2;
     while(*p) {                  // more moves to go
-       int expo = 1, dx, dy, x, y, mode, dirSet, retry=0, initial=0, jump=1;
+       int expo = 1, dx, dy, x, y, mode, dirSet, retry=0, initial=0, jump=1, skip = 0;
        if(*p == 'i') initial = 1, desc = ++p;
        while(islower(*p)) p++;  // skip prefixes
        if(!isupper(*p)) return; // syntax error: no atom
@@ -265,7 +265,7 @@ MovesFromString (Board board, int flags, int f, int r, char *desc, MoveCallback
                        } else desc++;
                        dirSet |= b;
                    }
-                   dirSet &= 0x99; if(!dirSet) dirSet = 0x99;
+                   dirSet &= 0x55; if(!dirSet) dirSet = 0x55;
                    break;
          case 'R': expo = 0;    // rook, slide
          case 'W':              // orthogonal atom (non-deg 4-fold)
@@ -315,10 +315,12 @@ MovesFromString (Board board, int flags, int f, int r, char *desc, MoveCallback
        if(expo > 1 && dx == 0 && dy == 0) {          // castling indicated by O + number
            mode |= 16; dy = 1;
        }
+       if(dy == 1) skip = jump - 1, jump = 1;        // on W & F atoms 'j' = skip first square
         do {
          for(dir=0, bit=1; dir<8; dir++, bit += bit) { // loop over directions
-           int i = expo, hop = mode, vx, vy;
+           int i = expo, j = skip, hop = mode, vx, vy;
            if(!(bit & dirSet)) continue;             // does not move in this direction
+           if(dy != 1) j = 0;                        // 
            vx = dx*rot[dir][0] + dy*rot[dir][1];     // rotate step vector
            vy = dx*rot[dir][2] + dy*rot[dir][3];
            x = f; y = r;                             // start square
@@ -327,6 +329,7 @@ MovesFromString (Board board, int flags, int f, int r, char *desc, MoveCallback
                if(y < 0 || y >= BOARD_HEIGHT) break; // vertically off-board: always done
                if(x <  BOARD_LEFT) { if(mode & 128) x += BOARD_RGHT - BOARD_LEFT; else break; }
                if(x >= BOARD_RGHT) { if(mode & 128) x -= BOARD_RGHT - BOARD_LEFT; else break; }
+               if(j) { j--; continue; }              // skip irrespective of occupation
                if(!jump    && board[y - vy + vy/2][x - vx + vx/2] != EmptySquare) break; // blocked
                if(jump > 1 && board[y - vy + vy/2][x - vx + vx/2] == EmptySquare) break; // no hop
                if(board[y][x] < BlackPawn)   occup = 1; else