code: public static void join(SAXSymbol left, SAXSymbol right) {
  
      // System.out.println(" performing the join of " + getPayload(left) + " and "
      // + getPayload(right));
  
      // check for an OLD digram existence - i.e. left must have a next symbol
      // if .n exists then we are joining TERMINAL symbols within the string, and must clean-up the
      // old digram
      if (left.n != null) {
        // System.out.println(" " + getPayload(left)
        // + " use to be in the digram table, cleaning up");
        left.deleteDigram();
      }
  
      // re-link left and right
      left.n = right;
      right.p = left;
    }
docs: Links left and right symbols together, i.e. removes this symbol from the string, also removing
  any old digram from the hash table.
  
  @param left the left symbol.
  @param right the right symbol.