title: ANTLR4: Using non-ASCII characters in token rules
body: <p>On page 74 of the ANTRL4 book it says that any Unicode character can be used in a grammar simply by specifying its codepoint in this manner:</p>
  
  <pre><code>'\uxxxx'
  </code></pre>
  
  <p>where <code>xxxx</code> is the hexadecimal value for the Unicode codepoint.</p>
  
  <p>So I used that technique in a token rule for an ID token:</p>
  
  <pre><code>grammar ID;
  
  id : ID EOF ;
  
  ID : ('a' .. 'z' | 'A' .. 'Z' | '\u0100' .. '\u017E')+ ;
  WS : [ \t\r\n]+ -&gt; skip ;
  </code></pre>
  
  <p>When I tried to parse this input:</p>
  
  <pre><code>Gŭnter
  </code></pre>
  
  <p>ANTLR throws an error, saying that it does not recognize <code>ŭ</code>. (The ŭ character is hex 016D, so it is within the range specified)</p>
  
  <p>What am I doing wrong please?</p>