NAME
    Business::AU::ABN - Format and validate ABNs ( Australian Business
    Number )

SYNOPSIS
      # Create a new ABN object
      use Business::AU::ABN;
      my $ABN = new Business::AU::ABN( '12 004 044 937' );
  
      # Validate the ABN
      $ABN->validate;
  
      # Validate in a single method call
      Business::AU::ABN->validate( '12 004 044 937' );
  
      # Validate in a single function call
      Business::AU::ABN::validate( '12 004 044 937' );
  
      # The validate function is also importable
      use Business::AU:ABN 'validate';
      validate( '12 004 044 937' );

DESCRIPTION
    The Australian Business Number ( ABN ) is a government allocated number
    required by all businesses in order to trade in Australia. It is
    intented to provide a central, universal, and unique identifier for all
    businesses.

    It's also rather neat, in that it is capable of self-validating. Much
    like a credit card number does, a simple algorithm applied to the digits
    can confirm that the number is valid. ( Although the business may not
    actually exist ). The checksum algorithm is specifically designed to
    catch situations in which you get two digits the wrong way around, or
    worse.

    Business::AU::ABN implements an object form of an ABN number. It has the
    ability to validate, and automatically reformates the number into the
    common and most prefered format, '01 234 567 890'.

    The object itself automatically stringifies to the it's formatted
    number, so you can do things like "print "Your ABN $ABN looks OK"" and
    other things of that nature.

  Highly flexible validation
    Apart from the algorithm itself, most of this module is aimed at making
    the validation mechanism as flexible and easy to use as possible.

    With this in mind, the "validate" sub can be accessed in ANY form, and
    will just "do what you mean". See the method details for more
    information.

METHODS
  new $string
    The "new" method creates a new "Business::AU::ABN" object. It expects as
    argument a defined string containing at least one non-whitespace
    character, or it will immediately return "undef".

    The method does not reformat or check the string provided in any way.

  to_string
    The "to_string" method returns the ABN as a string. This is the method
    called by the stringification overload. Providing that the ABN has been
    validated, this method will return the ABN in the correct '01 234 567
    890' format.

  $ABN->validate
    When called as a method on an object, "validate" does a number of simple
    format checks on the string originally provided, cleaning up and
    reformatting whitespace as needed. It then runs a checksum validation on
    the value.

    Returns true if the ABN is valid, or false if not

  Business::AU::ABN->validate $string
    When called as a static method, "validate" takes a string as an argument
    and attempts to validate it. When called in this form, the method is a
    little more flexible, and should tolerate just about any crap as an
    argument, returning false.

    Returns the correctly formatted ABN (which is also 'true' in boolean
    context) if the ABN is valid. Returns false otherwise.

  Business::AU::ABN::validate $string
    When called directly as a fully referenced function, "validate" responds
    in exactly the same was as for the static method above.

    Returns the correctly formatted ABN (which is also 'true' in boolean
    context) if the ABN is valid. Returns false otherwise.

  validate $string
    The "validate" function can also be imported to your package and used
    directly, as in the following example.

      use Business::AU::ABN 'validate';
      my $abn = '01 234 567 890';
      print "Your ABN is " . validate($abn) ? 'valid' : 'invalid';

    The imported function reponds identically to the fully referenced
    function and the static method.

    Returns the correctly formatted ABN (which is also 'true' in boolean
    context) if the ABN is valid. Returns false otherwise.

TO DO
    Add the method "acn" to derive the older Australian Company Number

SUPPORT
    Bugs should be reported via the CPAN bug tracker at

      http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Business%3A%3AAU%3A%3AABN

    For other issues, contact the author

AUTHORS
            Adam Kennedy ( maintainer )
            cpan@ali.as
            http://ali.as/

COPYRIGHT
    Copyright (c) 2003-2004 Adam Kennedy. All rights reserved. This program
    is free software; you can redistribute it and/or modify it under the
    same terms as Perl itself.

    The full text of the license can be found in the LICENSE file included
    with this module.