title: How to tell apart numeric scalars and string scalars in Perl?
body: <p>Perl usually converts numeric to string values and vice versa transparently. Yet there must be something which allows e.g. <code>Data::Dumper</code> to discriminate between both, as in this example:</p>
  
  <pre><code>use Data::Dumper;
  print Dumper('1', 1);
  
  # output:
  $VAR1 = '1';
  $VAR2 = 1;
  </code></pre>
  
  <p>Is there a Perl function which allows me to discriminate in a similar way whether a scalar's value is stored as number or as string?</p>