PT/PostalCode version 0.03
==========================

PT::PostalCode - Validates Portuguese postal codes

=head1 SYNOPSIS

  use PT::PostalCode;

  validate($postalcode);

  code_is_from_area($postalcode,$city);
  code_is_from_subarea($postalcode,$district);

  code_is_from($postalcode,$district,$city);

  range_from_subarea($district);

  code_is_valid($code);
  areas_of_code($code);
  subareas_of_code($code);

=head1 METHODS

=head2 code_is_from_area

Given a postal code and an area, returns true if that code exists in that area.

=head2 code_is_from_subarea

Given a postal code and a subarea, returns true if that code exists in that
subarea.

=head2 code_is_from

Given a code, a subarea and an area, returns true if that code exists in that
subarea of that area.

=head2 range_from_subarea

Given a subarea, returns a list with the ranges (minimum and maximum
values) of codes that subarea comprises. The return value is something
like [ (4900, 4935) ].

=head2 code_is_valid

Given a code, returns true if that code is valid.

=head2 areas_of_code

Given a code, returns a list of areas where that code is allowed.

=head2 subareas_of_code

Given a code, returns a list of subareas allowing that code.

=head1 DESCRIPTION

Validates Portuguese Postal Codes (that's the four digit code; in
order to validate the seven digit codes of the form xxxx-xxx we would
need a huge list of codes that would probably change every day).

=head1 PORTUGUESE POSTAL CODES

Regarding postal codes, Portugal is divided into areas and then into
subareas. This division does not correspond to the most expected one
(districts and then cities); instead, it was apparently made in a
way it would be easier to redirect mail.

Postal codes in Portugal do not seem to follow any particular rule
(but there was probably one in the beginning). There is no easy way of
saying where a given code belongs to.

Each subarea has a minimum and a maximum code. This means it only
allows for codes within that range. HOWEVER:

1) The existance of a range within a subarea does not imply the
existance of every single code in it.

2) The existance of a code within a subarea does not mean the code
does not exist in another area too.

THIS MEANS:

1) You can check if a code belongs to a certain area/subarea, but that
does not mean it doesn't also belong to other(s) area(s)/subarea(s).

2) Even if a code is within the range of a certain subarea, that does
not mean it is an existing code (that would need a huge list of codes,
which is always subject to alterations).

=head1 AUTHOR

Jose Castro, C<< <cog@cpan.org> >>

=head1 COPYRIGHT & LICENSE

Copyright 2004 Jose Castro, All Rights Reserved.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=cut