Free Hero Mesh

      switch(tokenv) {
        case OP_ADD: case OP_CLIMB: case OP_HEIGHT:
        case OP_LOC: case OP_MARK: case OP_SUB:
        case OP_QUEEN: case OP_ROOK: case OP_BISHOP:
        case OP_DIR: case OP_DIR_C: case OP_DIR_E: case OP_DIR_EC:
        case OP_OBJTOPAT: case OP_OBJBOTTOMAT: case OP_CUT: case OP_MUL:
        case OP_OBJABOVE: case OP_OBJBELOW: case OP_TRACE: case OP_NEXT:
        case OP_IMAGE: case OP_IMAGE_C:
        case 0x0200 ... 0x02FF: // message
        case 0x4000 ... 0x7FFF: // class
        case 0xC000 ... 0xFFFF: // message
          cl->codes[ptr++]=tokenv;
          break;
        case OP_BEGIN: case OP_IF:
          if(depth==31) ParseError("Too much pattern nesting\n");

(Climb <number>)
  Fail the match if the height here is greater than this number.

cut
  Discards the most recent choice point.

Dir
  Set the direction to the origin object's direction.

,Dir
  Set the direction to the matched object's direction.

=Dir
  Change the origin object's direction to the current direction.

=,Dir
  Change the matched object's direction to the current direction.

else
  Delimits alternatives within a block.

Height
  Fail the match if the origin object can climb here.

(Height <number>)
  Fail the match if the height here isn't greater than this number.

if
  Begin a block that can optionally match.

Image
  Match an object with the remembered class and image (if none is
  remembered, use the origin object's class and image).

,Image
  Remember the class and image of the currently matched object.

next
  Unconditionally fail the current attempt and try the next choice.

ObjAbove
  Match the object above the currently matched object.

ObjBelow

  Uint8 x=objects[obj]->x;
  Uint8 y=objects[obj]->y;
  Uint8 d=objects[obj]->dir;
  Uint32 n=VOIDLINK;
  Uint32 m;
  Uint16 g;
  Value v;
  ChoicePoint cp[MAXCHOICE];
  Uint8 cpi=0;
  Uint16 ccl=objects[obj]->class;
  Uint8 cim=objects[obj]->image;
  if(!x) return VOIDLINK;
  cp->depth=vstackptr;
  again: switch(code[ptr++]) {
    case 0 ... 7:
      n=VOIDLINK;
      x+=x_delta[code[ptr-1]];
      y+=y_delta[code[ptr-1]];

      cpi++;
      cp[cpi].x=x;
      cp[cpi].y=y;
      cp[cpi].dir=d;
      cp[cpi].depth=vstackptr;
      cp[cpi].ptr=code[ptr++];
      break;
    case OP_IMAGE:
      if(n!=VOIDLINK && ccl==objects[n]->class && cim==objects[n]->image) break;
      n=playfield[x+y*64-65];
      while(n!=VOIDLINK) {
        if(objects[n]->class==ccl && objects[n]->image==cim && !(objects[n]->oflags&OF_DESTROYED)) break;
        m=objects[n]->up;
      }
      if(n==VOIDLINK) goto fail;
      break;
    case OP_IMAGE_C:
      if(n==VOIDLINK) Throw("No object specified in pattern");
      ccl=objects[n]->class;
      cim=objects[n]->image;
      break;
    case OP_LOC:
      if(vstackptr>=VSTACKSIZE-2) Throw("Stack overflow");
      Push(NVALUE(x));
      Push(NVALUE(y));
      break;
    case OP_MARK:
      if(vstackptr>=VSTACKSIZE-1) Throw("Stack overflow");
      Push(UVALUE(0,TY_MARK));
      break;
    case OP_MUL:
      cp[cpi].x=x;
      cp[cpi].y=y;
      cp[cpi].dir=d;
      break;
    case OP_NEXT:
      goto fail;
    case OP_OBJABOVE:
      if(n==VOIDLINK) Throw("No object specified in pattern");
      n=obj_above(n);
      if(n==VOIDLINK) goto fail;
      break;
    case OP_OBJBELOW:
      if(n==VOIDLINK) Throw("No object specified in pattern");
      n=obj_below(n);
      if(n==VOIDLINK) goto fail;
      break;
    case OP_OBJBOTTOMAT:
      n=obj_bottom_at(x,y);
      if(n==VOIDLINK) goto fail;
      break;
    case OP_OBJTOPAT:
      n=obj_top_at(x,y);
      if(n==VOIDLINK) goto fail;
      break;
    case OP_QUEEN:
      if(cpi>=MAXCHOICE-8) Throw("Choice overflow");
      d=0;
      cpi+=7;
      cp[cpi].x=x;
      cp[cpi].y=y;