package HTML::FormFu::Constraint::Callback;

use strict;
use base 'HTML::FormFu::Constraint';

__PACKAGE__->mk_item_accessors( qw( callback ) );

sub constrain_value {
    my ( $self, $value, $params ) = @_;

    my $callback = $self->callback || sub {1};

    no strict 'refs';

    my $ok = $callback->( $value, $params );

    return $ok;
}

1;

__END__

=head1 NAME

HTML::FormFu::Constraint::Callback - Code Callback Constraint

=head1 SYNOPSIS

    $field->constraint({
        type => 'Callback',
        callback => \&foo,
    );

    ---
    elements:
      - type: Text
        name: foo
        constraints:
          - type: Callback
            callback: "main::my_constraint"

    sub foo {
        my ( $value, $params ) = @_;

        # return true or false
    }

=head1 DESCRIPTION

The first argument passed to the callback is the submitted value for the 
associated field. The second argument passed to the callback is a hashref of 
name/value pairs for all input fields.

This constraint doesn't honour the C<not()> value.

=head1 METHODS

=head2 callback

Arguments: \&code-reference

Arguments: "subroutine-name"

=head1 SEE ALSO

Is a sub-class of, and inherits methods from L<HTML::FormFu::Constraint>

L<HTML::FormFu>

=head1 LIMITATIONS

The callback code-ref is copied internally using L<Storable/dclone>. It 
seems that because of this, the coderef does not act as a true closure, and 
cannot refer to variables and subroutines that would otherwise be in scope. 
This need further investigation.

=head1 AUTHOR

Carl Franks C<cfranks@cpan.org>

=head1 LICENSE

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