}            return XML::XPath::Boolean->False;        }        else {            if ($lh_results->to_literal->value eq $rh_results->to_literal->value) {                return XML::XPath::Boolean->True;            }            return XML::XPath::Boolean->False;        }    }}sub op_nequals {    my ($node, $lhs, $rhs) = @_;    if (op_equals($node, $lhs, $rhs)->value) {        return XML::XPath::Boolean->False;    }    return XML::XPath::Boolean->True;}sub op_le {    my ($node, $lhs, $rhs) = @_;    op_gt($node, $rhs, $lhs);}sub op_ge {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        if ($lh_results->isa('XML::XPath::NodeSet') &&        $rh_results->isa('XML::XPath::NodeSet')) {        foreach my $lhnode ($lh_results->get_nodelist) {            foreach my $rhnode ($rh_results->get_nodelist) {                my $lhNum = XML::XPath::Number->new($lhnode->string_value);                my $rhNum = XML::XPath::Number->new($rhnode->string_value);                if ($lhNum->value >= $rhNum->value) {                    return XML::XPath::Boolean->True;                }            }        }        return XML::XPath::Boolean->False;    }    elsif (($lh_results->isa('XML::XPath::NodeSet') ||            $rh_results->isa('XML::XPath::NodeSet')) &&            (!$lh_results->isa('XML::XPath::NodeSet') ||             !$rh_results->isa('XML::XPath::NodeSet'))) {        # (that says: one is a nodeset, and one is not a nodeset)        my ($nodeset, $other);        my ($true, $false);        if ($lh_results->isa('XML::XPath::NodeSet')) {            $nodeset = $lh_results;            $other = $rh_results;            # we do this because unlike ==, these ops are direction dependant            ($false, $true) = (XML::XPath::Boolean->False, XML::XPath::Boolean->True);        }        else {            $nodeset = $rh_results;            $other = $lh_results;            # ditto above comment            ($true, $false) = (XML::XPath::Boolean->False, XML::XPath::Boolean->True);        }                # True if and only if there is a node in the        # nodeset such that the result of performing        # the comparison on <type>(string_value($node))        # is true.        foreach my $node ($nodeset->get_nodelist) {            if ($node->to_number->value >= $other->to_number->value) {                return $true;            }        }        return $false;    }    else { # Neither is a nodeset        if ($lh_results->isa('XML::XPath::Boolean') ||            $rh_results->isa('XML::XPath::Boolean')) {            # if either is a boolean            if ($lh_results->to_boolean->to_number->value                    >= $rh_results->to_boolean->to_number->value) {                return XML::XPath::Boolean->True;            }        }        else {            if ($lh_results->to_number->value >= $rh_results->to_number->value) {                return XML::XPath::Boolean->True;            }        }        return XML::XPath::Boolean->False;    }}sub op_gt {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        if ($lh_results->isa('XML::XPath::NodeSet') &&        $rh_results->isa('XML::XPath::NodeSet')) {        foreach my $lhnode ($lh_results->get_nodelist) {            foreach my $rhnode ($rh_results->get_nodelist) {                my $lhNum = XML::XPath::Number->new($lhnode->string_value);                my $rhNum = XML::XPath::Number->new($rhnode->string_value);                if ($lhNum->value > $rhNum->value) {                    return XML::XPath::Boolean->True;                }            }        }        return XML::XPath::Boolean->False;    }    elsif (($lh_results->isa('XML::XPath::NodeSet') ||            $rh_results->isa('XML::XPath::NodeSet')) &&            (!$lh_results->isa('XML::XPath::NodeSet') ||             !$rh_results->isa('XML::XPath::NodeSet'))) {        # (that says: one is a nodeset, and one is not a nodeset)        my ($nodeset, $other);        my ($true, $false);        if ($lh_results->isa('XML::XPath::NodeSet')) {            $nodeset = $lh_results;            $other = $rh_results;            # we do this because unlike ==, these ops are direction dependant            ($false, $true) = (XML::XPath::Boolean->False, XML::XPath::Boolean->True);        }        else {            $nodeset = $rh_results;            $other = $lh_results;            # ditto above comment            ($true, $false) = (XML::XPath::Boolean->False, XML::XPath::Boolean->True);        }                # True if and only if there is a node in the        # nodeset such that the result of performing        # the comparison on <type>(string_value($node))        # is true.        foreach my $node ($nodeset->get_nodelist) {            if ($node->to_number->value > $other->to_number->value) {                return $true;            }        }        return $false;    }    else { # Neither is a nodeset        if ($lh_results->isa('XML::XPath::Boolean') ||            $rh_results->isa('XML::XPath::Boolean')) {            # if either is a boolean            if ($lh_results->to_boolean->value > $rh_results->to_boolean->value) {                return XML::XPath::Boolean->True;            }        }        else {            if ($lh_results->to_number->value > $rh_results->to_number->value) {                return XML::XPath::Boolean->True;            }        }        return XML::XPath::Boolean->False;    }}sub op_lt {    my ($node, $lhs, $rhs) = @_;    op_gt($node, $rhs, $lhs);}sub op_plus {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        my $result =        $lh_results->to_number->value            +        $rh_results->to_number->value            ;    return XML::XPath::Number->new($result);}sub op_minus {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        my $result =        $lh_results->to_number->value            -        $rh_results->to_number->value            ;    return XML::XPath::Number->new($result);}sub op_div {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);    my $result = eval {        $lh_results->to_number->value            /        $rh_results->to_number->value            ;    };    if ($@) {        # assume divide by zero        # This is probably a terrible way to handle this!         # Ah well... who wants to live forever...        return XML::XPath::Literal->new('Infinity');    }    return XML::XPath::Number->new($result);}sub op_mod {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        my $result =        $lh_results->to_number->value            %        $rh_results->to_number->value            ;    return XML::XPath::Number->new($result);}sub op_mult {    my ($node, $lhs, $rhs) = @_;    my $lh_results = $lhs->evaluate($node);    my $rh_results = $rhs->evaluate($node);        my $result =        $lh_results->to_number->value            *        $rh_results->to_number->value            ;    return XML::XPath::Number->new($result);}sub op_union {    my ($node, $lhs, $rhs) = @_;    my $lh_result = $lhs->evaluate($node);    my $rh_result = $rhs->evaluate($node);        if ($lh_result->isa('XML::XPath::NodeSet') &&            $rh_result->isa('XML::XPath::NodeSet')) {        my %found;        my $results = XML::XPath::NodeSet->new;        foreach my $lhnode ($lh_result->get_nodelist) {            $found{"$lhnode"}++;            $results->push($lhnode);        }        foreach my $rhnode ($rh_result->get_nodelist) {            $results->push($rhnode)                    unless exists $found{"$rhnode"};        }                $results->sort;        return $results;    }    die "Both sides of a union must be Node Sets\n";}sub filter_by_predicate {    my $self = shift;    my ($nodeset, $predicate) = @_;        # See spec section 2.4, paragraphs 2 & 3:    # For each node in the node-set to be filtered, the predicate Expr    # is evaluated with that node as the context node, with the number    # of nodes in the node set as the context size, and with the    # proximity position of the node in the node set with respect to    # the axis as the context position.        if (!ref($nodeset)) { # use ref because nodeset has a bool context        die "No nodeset!!!";    }    #    warn "Filter by predicate: $predicate\n";        my $newset = XML::XPath::NodeSet->new();        for(my $i = 1; $i <= $nodeset->size; $i++) {        # set context set each time 'cos a loc-path in the expr could change it        $self->{pp}->set_context_set($nodeset);        $self->{pp}->set_context_pos($i);        my $result = $predicate->evaluate($nodeset->get_node($i));        if ($result->isa('XML::XPath::Boolean')) {            if ($result->value) {                $newset->push($nodeset->get_node($i));            }        }        elsif ($result->isa('XML::XPath::Number')) {            if ($result->value == $i) {                $newset->push($nodeset->get_node($i));            }        }        else {            if ($result->to_boolean->value) {                $newset->push($nodeset->get_node($i));            }        }    }        return $newset;}1;