l integer */
	      int i_val = 0;
	      do {
	        i_val = i_val * 10 + (next_char - '0');
	        advance();
	      } while (next_char &gt;= '0' &amp;&amp; next_char &lt;= '9');
	    return sf.newSymbol("NUMBER",sym.NUMBER, new Integer(i_val));

	    case ';': advance(); return sf.newSymbol("SEMI",sym.SEMI);
	    case '+': advance(); return sf.newSymbol("PLUS",sym.PLUS);
	    case '-': advance(); return sf.newSymbol("MINUS",sym.MINUS);
	    case '*': advance(); return sf.newSymbol("TIMES",sym.TIMES);