NAME

Poz::Types::null - Null type validation for Poz::Types

SYNOPSIS

use Poz qw/z/;

my $null_validator = z->null;

$null_validator->parse(undef); # returns undef
$null_validator->parse(1); # returns error message

my $array_with_null_or_number = z->array(z->union(z->null, z->number));
$array_with_null_or_number->parse([undef, 1]); # returns [undef, 1]
$array_with_null_or_number->parse([1, 2]); # returns [1, 2]
$array_with_null_or_number->parse([undef, "a"]); # returns error message

DESCRIPTION

This module provides a null type validator for Poz::Types. It can be used to validate that a value is undef.

METHODS

rule

my $error = $null_validator->rule($value);

Validates the given value. Returns an error message if the value is not undef, otherwise returns undef.

LICENSE

Copyright (C) ytnobody.

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

AUTHOR

ytnobody <ytnobody@gmail.com>