title: Semantic predicates in ANTLR4?
body: <p>How would you translate this portion of code written in ANTLR 3 into ANTLR 4?</p>
  
  <pre><code>expr: (Identifier '.')=&gt; (refIdentifier)
    | (Identifier '!')=&gt; (refIdentifier)
    | (Identifier '=&gt;')=&gt; (lambdaExpression);
  </code></pre>
  
  <p>I mean this kind of semantic predicate does not seem to exist now. What could I use Instead?</p>