code: public int precedence(ParserToken token) {
        if (isInfix(token)) {
           return infixHandlers.get(token.type).precedence();
        }
        return 0;
     }
docs: Gets the precedence of the associated infix handler.
  
  @param token The token whose handler we want precedence for
  @return the precedence of the associated infix handler or 0 if there is none.