Using BNF to create regex's

While reading the VB Language Spec today I decided to attempt to follow the grammar syntax for matching DateTime Literals:

     http://msdn.microsoft.com/library/en-us/vbls7/html/vblrfvbspec2_4_6.asp?frame=true

DateLiteral ::= # [ Whitespace+ ] DateOrTime [ Whitespace+ ] #
DateOrTime ::=
   DateValue Whitespace+ TimeValue |
   DateValue |
   TimeValue
DateValue ::=
   MonthValue / DayValue / YearValue |
   MonthValue – DayValue - YearValue
TimeValue ::=
   HourValue : MinuteValue [ : SecondValue ] [ WhiteSpace+ ] [ AMPM ]
MonthValue ::= IntLiteral
DayValue ::= IntLiteral
YearValue ::= IntLiteral
HourValue ::= IntLiteral
MinuteValue ::= IntLiteral
SecondValue ::= IntLiteral
AMPM ::= AM | PM

The resulting pattern can be seen (fully commented) here:

     http://www.regexlib.com/REDetails.aspx?regexp_id=638