=head1 UK Postcode matching in Perl

This is a test bed program to validate UK postcodes
and also to extract the various key elements into
other variables.

The section of a postcode up to the mandatory space
is known as the "in" as it's inbound to a sorting
office, and the section after the space is known as
the "out" as it's used to sort at the sorting office
into individual post staff delivery runs.

I have used the \b boundary condition in this code -
I did NOT want to anchor to start or end of line, but
neither did I want to match postcodes that start within
a word. \b (word boundary match) is a happy compromise.

=cut

while (1) {
print ("please enter delivery postcode: ");
chop ($sendto = <STDIN>);

if ($sendto =~
/\b(([A-Z]{1,2})\d[0-9A-Z]?) +(\d[A-Z]{2})\b/) {
        print "Yay ---- in $1 and out $3 - $2\n";
} else {
        print "OOOOOOps\n";
}
}

__END__

Sample output

Dorothy:p82 grahamellis$ perl pcode
please enter delivery postcode: SN12 7NY
Yay ---- in SN12 and out 7NY - SN
please enter delivery postcode: G51 3AC
Yay ---- in G51 and out 3AC - G
please enter delivery postcode: SW1A 1AA
Yay ---- in SW1A and out 1AA - SW
please enter delivery postcode: RDG1 7NW
OOOOOOps
please enter delivery postcode: RG21 1EE
Yay ---- in RG21 and out 1EE - RG
please enter delivery postcode: ^C
Dorothy:p82 grahamellis$