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# From XProlog
sub value {

    # int i, res = 0;
    my $self = shift;
    my ( $i, $res ) = ( 0, 0 );

    unless ( $self->{bound} ) {
        my $term = $self->to_string;
        croak("Tried to to get value of unbound term ($term)");
    }
    return $self->{ref}->value if $self->{deref};
    my $functor = $self->getfunctor;
    my $arity   = $self->getarity;
    if ( 'rnd' eq $functor && 1 == $arity ) {

        # implement rand
    }
    if ( $arity < 2 ) {
        my $term = $self->to_string;
        croak("Term ($term) is not binary");
    }
    my $arg0 = $self->{args}[0]->value;
    my $arg1 = $self->{args}[1]->value;

    return $arg0 + $arg1 if 'plus'  eq $functor;
    return $arg0 - $arg1 if 'minus' eq $functor;
    return $arg0 * $arg1 if 'mult'  eq $functor;
    return $arg0 / $arg1 if 'div'   eq $functor;
    return $arg0 % $arg1 if 'mod'   eq $functor;
    return $arg0**$arg1  if 'pow'   eq $functor;
    croak("Unknown operator ($functor)");
}

1;

__END__

=head1 NAME

AI::Prolog::Term - Create Prolog Terms.

=head1 SYNOPSIS

 my $query = Term->new("steals(Somebody, Something).");

=head1 DESCRIPTION

See L<AI::Prolog|AI::Prolog> for more information.  If you must know more,
there are plenty of comments sprinkled through the code.

=head1 BUGS

A query using C<[HEAD|TAIL]> syntax does not bind properly with the C<TAIL>
variable when returning a result object.  This bug can be found in the
C<_to_data> method of this class.

=head1 SEE ALSO

W-Prolog:  L<http://goanna.cs.rmit.edu.au/~winikoff/wp/>

Michael BartE<225>k's online guide to programming Prolog:
L<http://kti.ms.mff.cuni.cz/~bartak/prolog/index.html>

=head1 AUTHOR

Curtis "Ovid" Poe, E<lt>moc tod oohay ta eop_divo_sitrucE<gt>

Reverse the name to email me.

This work is based on W-Prolog, L<http://goanna.cs.rmit.edu.au/~winikoff/wp/>,
by Dr. Michael Winikoff.  Many thanks to Dr. Winikoff for granting me
permission to port this.

=head1 COPYRIGHT AND LICENSE

Copyright 2005 by Curtis "Ovid" Poe

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

=cut