Implement Betza t modifier for hop-own

The 't' modifier will restrict any form of hopping as specified by
p or g modifiers to friendly pieces. This only works on non-final legs.

diff --git a/moves.c b/moves.c
index e57672e..bc5f415 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -335,17 +335,18 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
        }
        if(mine == 2 && tx < 0) dirSet = dirSet >> 4 | dirSet << 4 & 255;   // invert black moves
        mode = 0;                // build mode mask
-       if(*desc == 'm') mode |= 4, desc++;
-       if(*desc == 'c') mode |= his, desc++;
-       if(*desc == 'd') mode |= mine, desc++;
-       if(*desc == 'e') mode |= 8, desc++;
-       if(*desc == 'p') mode |= 32, desc++;
-       if(*desc == 'g') mode |= 64, desc++;
-       if(*desc == 'o') mode |= 128, desc++;
-       if(*desc == 'y') mode |= 512, desc++;
-       if(*desc == 'n') jump = 0, desc++;
-       while(*desc == 'j') jump++, desc++;
-       if(*desc == 'a') cont = ++desc;
+       if(*desc == 'm') mode |= 4, desc++;           // move to empty
+       if(*desc == 'c') mode |= his, desc++;         // capture foe
+       if(*desc == 'd') mode |= mine, desc++;        // destroy (capture friend)
+       if(*desc == 'e') mode |= 8, desc++;           // e.p. capture last mover
+       if(*desc == 't') mode |= 16, desc++;          // exclude enemies as hop platform ('test')
+       if(*desc == 'p') mode |= 32, desc++;          // hop over occupied
+       if(*desc == 'g') mode |= 64, desc++;          // hop and toggle range
+       if(*desc == 'o') mode |= 128, desc++;         // wrap around cylinder board
+       if(*desc == 'y') mode |= 512, desc++;         // toggle range on empty square
+       if(*desc == 'n') jump = 0, desc++;            // non-jumping
+       while(*desc == 'j') jump++, desc++;           // must jump (on B,R,Q: skip first square)
+       if(*desc == 'a') cont = ++desc;               // move again after doing what preceded it
        if(isdigit(*++p)) expo = atoi(p++);           // read exponent
        if(expo > 9) p++;                             // allow double-digit
        desc = p;                                     // this is start of next move
@@ -353,7 +354,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
                       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
-           mode |= 16; dy = 1;
+           mode |= 1024; dy = 1;
        }
         if(!cont) {
            if(!(mode & 15)) mode = his + 4;          // no mode spec, use default = mc
@@ -394,6 +395,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
                if(board[y][x] < EmptySquare) occup = 0x102; else
                                              occup = 4;
                if(cont) {                            // non-final leg
+                 if(mode&16 && his&occup) occup &= 3;// suppress hopping foe in t-mode
                  if(occup & mode) {                  // valid intermediate square, do continuation
                    if(occup & mode & 0x104)          // no side effects, merge legs to one move
                        MovesFromString(board, flags, f, r, x, y, dir, cont, cb, cl);
@@ -415,7 +417,7 @@ MovesFromString (Board board, int flags, int f, int r, int tx, int ty, int angle
                if(mode & 8 && y == board[EP_RANK] && occup == 4 && board[EP_FILE] == x) { // to e.p. square
                    cb(board, flags, mine == 1 ? WhiteCapturesEnPassant : BlackCapturesEnPassant, r, f, y, x, cl);
                }
-               if(mode & 16) {              // castling
+               if(mode & 1024) {            // castling
                    i = 2;                   // kludge to elongate move indefinitely
                    if(occup == 4) continue; // skip empty squares
                    if(x == BOARD_LEFT   && board[y][x] == initialPosition[y][x]) // reached initial corner piece