title: How can I dereference a hashref constant?
body: <p>Let's say I have a hashref constant like the following:</p>
  
  <pre><code>use constant DOGS =&gt; {
      Lassie =&gt; 'collie',
      Benji  =&gt; 'mutt',
      Scooby =&gt; 'great dane',
      Goofy  =&gt; '???'
  };
  </code></pre>
  
  <p>How can I dereference it properly to get say.. they keys out of it?</p>
  
  <pre><code>warn ref DOGS; # HASH at untitled line 12.
  warn keys( %{DOGS} ); # Warning: something's wrong (empty list)
  warn keys( DOGS ); # Type of arg 1 to keys must be hash (not constant item)
  </code></pre>
  
  <p>The following is the only way I can seem to make it work:</p>
  
  <pre><code>my $dogs = DOGS;
  warn keys( %$dogs ); # LassieBenjiGoofyScooby at untitled line 15.
  </code></pre>
  
  <p>What am I doing wrong?</p>