title: ANTLRWorks warning 'no start rule'
body: <p>please help a newbie to understand this 
  warning in ANTLWorks:</p>
  
  <blockquote>
    <p>[11:10:15] warning(138): BooleanExpr.g:0:1: grammar BooleanExpr: no start rule (no rule can obviously be followed by EOF)</p>
  </blockquote>
  
  <p>This is how definition of my grammar looks like:</p>
  
  <pre><code>grammar BooleanExpr;
  booleanExpr
      :   andExpr ('OR' andExpr)*;
  andExpr :   notExpr (('AND' | ' ' ) notExpr)*;
  notExpr :   kppExpr ('NOT' kppExpr);
  kppExpr :   keywordExpr|phraseExpr|proximityExpr|'(' booleanExpr ')';
  keywordExpr
      :CHAR+;
  phraseExpr
      :   '"' keywordExpr '"';
  proximityExpr
      :   keywordExpr|phraseExpr '~' INT;
  CHAR    :   ('A'..'Z') | ('a'..'z');
  INT :   '0'..'9'+;
  </code></pre>
  
  <p>Thanks a lot!</p>