title: recognize fractional numbers in JFlex 1.4.3
body: <p>in my SL.lex file i have this regular expression for fractional numbers:</p>
  
  <pre><code>Digit = [1-9]
  Digit0 = 0|{Digit}
  Num = {Digit} {Digit0}*
  Frac = {Digit0}* {Digit}
  Pos = {Num} | '.' {Frac} | 0 '.' {Frac} | {Num} '.' {Frac}
  PosOrNeg = -{Pos} | {Pos}
  
  Numbers = 0 | {PosOrNeg}
  </code></pre>
  
  <p>and then in </p>
  
  <pre><code>/* literals */
  {Numbers}            { return new Token(yytext(), sym.NUM, getLineNumber()); }
  </code></pre>
  
  <p>but every time i try to recognize a number with a dot, it fails and i get an error.</p>
  
  <p>instead of '.' i also tried <code>\\.</code>,<code>\.</code>,<code>"."</code>, but every time it fails.</p>