=head1 NAME

Webservice::InterMine::Constraint::Logic - the logic for combining constraints on a path in a PathQuery

=head1 SYNOPSIS

=head1 AUTHOR

FlyMine C<< <support@flymine.org> >>

=head1 BUGS

Please report any bugs or feature requests to C<support@flymine.org>.

=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Webservice::InterMine::PathQuery::Constraint

You can also look for information at:

=over 4

=item * FlyMine

L<http://www.flymine.org>

=back

=head1 COPYRIGHT & LICENSE

Copyright 2009 FlyMine, all rights reserved.

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

=head1 FUNCTIONS

=cut

# This class exists to provide overloaded operators to ::Constraint and ::ConstraintSet
# as such there are no public methods, but only the operators "&" and "|"
# These allow combinations such as $query->logic($con1 & ($con2 & $con3));

package Webservice::InterMine::Constraint::Role::Logical;

use MooseX::Role::WithOverloading;
use Webservice::InterMine::Constraint::LogicalSet;

use overload 
    '&' => \&_and,
    '|' => \&_or,
    fallback => 1;


# This method overloads &
sub _and {
    return _make_node('and', @_);
}

# This method overloads |
sub _or {
    return _make_node('or', @_);
}

sub _make_node {
    my ($op, $l, $r, $rev) = @_;
    ($l, $r) = ($r, $l) if ($rev);
    return Webservice::InterMine::Constraint::LogicalSet->new(op    => $op,
						  left  => $l,
						  right => $r);
}

1;