#! /usr/bin/perl -w

use strict;

use Geo::Postcodes::DK 0.30;

################################################################################
#                                                                              #
#                                 static_dk                                    #
#                                ------------                                  #
#              Arne Sommer - perl@bbop.org - 12. September 2006                #
#                                                                              #
################################################################################

use Digest::SHA1;

my @arg1 = ('postcode' => '.(.)\1.');

print "All danish postcodes where the second and third digits are identical:\n";

my @postcodes = Geo::Postcodes::DK::selection(@arg1);

print join ",", @postcodes; print ".\n\n";

################################################################################

print "As above, but with the addition of a procedure:\n";

my @arg2 = (@arg1, 'procedure' => \&selector_procedure);

@postcodes = Geo::Postcodes::DK::selection(@arg2);

print join ",", @postcodes; print ".\n\n";

################################################################################

## This one computes the SHA1-digest of the postal location, and returns true
## if the there is a lower case letter a-z among the 11th to 16th characters.

sub selector_procedure
{
  my $postcode = shift;

  my $location = Geo::Postcodes::DK::location_of($postcode);

  my $digest = Digest::SHA1::sha1($location);

  return 1 if substr($digest, 10, 5) =~ /[a-z]/;
  return 0;
}