Date/Time modules - any without default months/days?
 

It seems that DateTime and Class::Date both will default month and day
to "1" if you try to create an object with just a year:

$d = new("2003")

gives $d->month = 1

Is there a module that doesn't do this? I need to be able to create
date objects which are potentially just a year and need to be able
also to distinguish between really passing month = 1 and having it
default to 1. It seems very odd these modules don't just return
"undef" when no month is passed, for example.