NAME

String::BlackWhiteList - match a string against a blacklist and a whitelist

SYNOPSIS

use String::BlackWhiteList;

use constant BLACKLIST => (
    'POST',
    'PO',
    'P O',
    'P O BOX',
    'P.O.',
    'P.O.B.',
    'P.O.BOX',
    'P.O. BOX',
    'P. O.',
    'P. O.BOX',
    'P. O. BOX',
    'POBOX',
);

use constant WHITELIST => (
    'Post Road',
    'Post Rd',
    'Post Street',
    'Post St',
    'Post Avenue',
    'Post Av',
    'Post Alley',
    'Post Drive',
);

my @ok = (
    'Post Road 123',
    'Post Rd 123',
    'Post Street 123',
    'Post St 123',
    'Post Avenue 123',
);

my @not_ok = (
    'Post',
    'P.O. BOX 37',
    'P.O. BOX 37, Post Drive 9',
    'Post Street, P.O.B.',
);

plan tests => @ok + @not_ok;

my $matcher = String::BlackWhiteList->new(
    blacklist => [ BLACKLIST ],
    whitelist => [ WHITELIST ]
)->update;

ok( $matcher->valid($_), "[$_] valid")   for @ok;
ok(!$matcher->valid($_), "[$_] invalid") for @not_ok;

DESCRIPTION

Using this class you can match strings against a blacklist and a whitelist. The matching algorithm is explained in the valid() method's documentation.

METHODS

new

Constructs a matcher object.

blacklist

Is an array accessor per Class::Accessor::Complex. Use it to maintain the list of (sub-)strings you consider blacklisted.

whitelist

Is an array accessor per Class::Accessor::Complex. Use it to maintain the list of (sub-)strings you consider whitelisted.

black_re

The actual regular expression (preferably created by qr//) used for blacklist testing.

white_re

The actual regular expression (preferably created by qr//) used for whitelist testing.

update

Takes the blacklist from blacklist(), generates a regular expression that matches any string in the blacklist and sets the regular expression on black_re().

Also takes the whitelist from whitelist(), generates a regular expression that matches any string in the whitelist and sets the regular expression on white_re().

If you set a black_re() and a white_re() yourself, you shouldn't use <update(), of course.

valid

Takes a string and tries to determine whether it is valid according to the blacklist and the whitelist. This is the algorithm used to determine validity:

If the string matches the whitelist, then the part of the string that didn't match the whitelist is checked against the blacklist. If the remainder matches the blacklist, the string is still considered invalid. If not, it is considered valid.

Consider the example of P.O. BOX 37, Post Drive 9 in the "SYNOPSIS". The Post Drive matches the whitelist, but the P.O. BOX matches the blacklist, so the string is still considered invalid.

If the string doesn't match the whitelist, but it matches the blacklist, then it is considered invalid.

If the string matches neither the whitelist nor the blacklist, it is considered valid.

Undefined values and empty strings are considered valid. This may seem strange, but there is no indication that they are invalid and in dubio pro reo.

TAGS

If you talk about this module in blogs, on del.icio.us or anywhere else, please use the stringblackwhitelist tag.

BUGS AND LIMITATIONS

No bugs have been reported.

Please report any bugs or feature requests to bug-string-blackwhitelist@rt.cpan.org, or through the web interface at http://rt.cpan.org.

INSTALLATION

See perlmodinstall for information and options on installing Perl modules.

AVAILABILITY

The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit <http://www.perl.com/CPAN/> to find a CPAN site near you. Or see <http://www.perl.com/CPAN/authors/id/M/MA/MARCEL/>.

AUTHOR

Marcel Grünauer, <marcel@cpan.org>

COPYRIGHT AND LICENSE

Copyright 2007 by Marcel Grünauer

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