While on the discussion of code tags, let me mention the x regexp modifier. It lets you use whitespace
in your regular expressions for greater readability.

m/[0-3]?
  [0-9(th)?(st)?(nd)?(rd)?]
  \s+
  (Jan(uary)?|
   Feb(ruary)?|
   Mar(ch)?|
   Apr(il)?|
   May|
   Jun(e)?|
   Jul(y)?|
   Aug(ust)?|
   Sep(tember)?|
   Oct(ober)?|
   Nov(ember)?|
   Dec(ember)?)
  \s+
  [0-9]?[0-9]?[0-9][0-9]/igx;
[download]

The extra whitespace makes it far easier to follow (and doesn't make the browser screen width 4000 pixels wide. ;-)

Russ