an>
      /rule(expression):	""
    /grammar(calc):	""
    <span class="preprocessor">-------------------------
    Parsing succeeded
    result = 3
    -------------------------</span></code></pre>

<p> We typed in &quot;1 + 2&quot;. Notice that there are two successful branches
  from the top rule <tt>expr</tt>. The text in red is generated by the parser's
  semantic actions while the others are generated by the debug-diagnostics of
  our rules. Notice how the first <tt>integer</tt> rule took &quot;1&quot