title: parsing date in a .NET command line tool using RegEx
body: <p>In a vb.net command line tool I am working on there is a command called period P:
  I want to specify dates in the following formats</p>
  
  <pre><code>P:2009                       'translate this to 01.01.2009 to 31.12.2009
  P:2008 To 2010               'translate this to 01.01.2008 to 31.12.2010
  P:01.01.2012 To 22.11.2013   'stays the same
  </code></pre>
  
  <p>After I get the text that comes after P: I want to validate it using regex and add the missing parts to it since I will use it in an sql command.</p>
  
  <p>Any adivce?</p>