sub regexp ($;$) {
my $self = shift;
my $delim = qr/:?\:|\/|-/; # "non memory" cluster: no backreference
- my $format = (@_) ? shift : $self->{'dateformat'}; # w/o arg. relies on dateformat being defined
+ my $format = (@_) ? _recognize_format(shift) : ($self->{'dateformat'} || _prefformat());
+
+ # Extra layer of checking $self->{'dateformat'}.
+ # Why? Because it is assumed you might want to check regexp against an *instantiated* Dates object as a
+ # way of saying "does this string match *whatever* format that Dates object is?"
+
($format eq 'sql') and
return qr/^(\d{4})(\d{2})(\d{2})(?:\s{4}(\d{2})(\d{2})(\d{2}))?/;
($format eq 'iso') and