# $Id: Expr.pm,v 1.20 2003/01/26 19:33:24 matt Exp $
package XML::XPathEngine::Expr;
use strict;
sub new {
my $class = shift;
my ($pp) = @_;
bless { predicates => [], pp => $pp }, $class;
}
sub as_string {
my $self = shift;
local $^W; # Use of uninitialized value! grrr
my $string = "(" . $self->{lhs}->as_string;
$string .= " " . $self->{op} . " " if defined $self->{op};
$string .= $self->{rhs}->as_string if defined $self->{rhs};
$string .= ")";
foreach my $predicate (@{$self->{predicates}}) {
$string .= "[" . $predicate->as_string . "]";
}
return $string;
}
sub as_xml {
my $self = shift;
local $^W; # Use of uninitialized value! grrr
my $string;
if (defined $self->{op}) {
$string .= $self->op_xml();
}
else {
$string .= $self->{lhs}->as_xml();
}
foreach my $predicate (@{$self->{predicates}}) {
$string .= "<Predicate>\n" . $predicate->as_xml() . "</Predicate>\n";
}
return $string;
}
sub op_xml {
my $self = shift;
my $op = $self->{op};
my $tag;
for ($op) {
/^or$/ && do {
$tag = "Or";
};
/^and$/ && do {
$tag = "And";
};
/^=$/ && do {
$tag = "Equals";
};
/^!=$/ && do {
$tag = "NotEquals";
};
/^<=$/ && do {
$tag = "LessThanOrEquals";
};
/^>=$/ && do {
$tag = "GreaterThanOrEquals";
};
/^>$/ && do {
$tag = "GreaterThan";
};
/^<$/ && do {
$tag = "LessThan";
};
/^\+$/ && do {
$tag = "Plus";
};
/^-$/ && do {
$tag = "Minus";
};
/^div$/ && do {
$tag = "Div";
};
/^mod$/ && do {
$tag = "Mod";
};
/^\*$/ && do {
$tag = "Multiply";
};
/^\|$/ && do {
$tag = "Union";
};
}
return "<$tag>\n" . $self->{lhs}->as_xml() . $self->{rhs}->as_xml() . "</$tag>\n";
}
sub set_lhs {
my $self = shift;
$self->{lhs} = $_[0];
}
sub set_op {
my $self = shift;
$self->{op} = $_[0];
}
sub set_rhs {
my $self = shift;
$self->{rhs} = $_[0];
}
sub push_predicate {
my $self = shift;
die "Only 1 predicate allowed on FilterExpr in W3C XPath 1.0"
if @{$self->{predicates}};
push @{$self->{predicates}}, $_[0];
}
sub get_lhs { $_[0]->{lhs}; }
sub get_rhs { $_[0]->{rhs}; }
sub get_op { $_[0]->{op}; }
sub evaluate {
my $self = shift;
my $node = shift;
# If there's an op, result is result of that op.
# If no op, just resolve Expr
# warn "Evaluate Expr: ", $self->as_string, "\n";
my $results;
if ($self->{op}) {
die ("No RHS of ", $self->as_string) unless $self->{rhs};
$results = $self->op_eval($node);
}
else {
$results = $self->{lhs}->evaluate($node);
}
if (my @predicates = @{$self->{predicates}}) {
if (!$results->isa('XML::XPathEngine::NodeSet')) {
die "Can't have predicates execute on object type: " . ref($results);
}
# filter initial nodeset by each predicate
foreach my $predicate (@{$self->{predicates}}) {
$results = $self->filter_by_predicate($results, $predicate);
}
}
return $results;
}
sub op_eval {
my $self = shift;
my $node = shift;
my $op = $self->{op};
for ($op) {
/^or$/ && do {
return op_or($node, $self->{lhs}, $self->{rhs});
};
/^and$/ && do {
return op_and($node, $self->{lhs}, $self->{rhs});
};
/^=~$/ && do {
return op_match($node, $self->{lhs}, $self->{rhs});
};
/^!~$/ && do {
return op_not_match($node, $self->{lhs}, $self->{rhs});
};
/^=$/ && do {
return op_equals($node, $self->{lhs}, $self->{rhs});
};
/^!=$/ && do {
return op_nequals($node, $self->{lhs}, $self->{rhs});
};
/^<=$/ && do {
return op_le($node, $self->{lhs}, $self->{rhs});
};
/^>=$/ && do {
return op_ge($node, $self->{lhs}, $self->{rhs});
};
/^>$/ && do {
return op_gt($node, $self->{lhs}, $self->{rhs});
};
/^<$/ && do {
return op_lt($node, $self->{lhs}, $self->{rhs});
};
/^\+$/ && do {
return op_plus($node, $self->{lhs}, $self->{rhs});
};
/^-$/ && do {
return op_minus($node, $self->{lhs}, $self->{rhs});
};
/^div$/ && do {
return op_div($node, $self->{lhs}, $self->{rhs});
};
/^mod$/ && do {
return op_mod($node, $self->{lhs}, $self->{rhs});
};
/^\*$/ && do {
return op_mult($node, $self->{lhs}, $self->{rhs});
};
/^\|$/ && do {
return op_union($node, $self->{lhs}, $self->{rhs});
};
die "No such operator, or operator unimplemented in ", $self->as_string, "\n";
}
}
# Operators
use XML::XPathEngine::Boolean;
sub op_or {
my ($node, $lhs, $rhs) = @_;
if($lhs->evaluate($node)->to_boolean->value) {
return XML::XPathEngine::Boolean->True;
}
else {
return $rhs->evaluate($node)->to_boolean;
}
}
sub op_and {
my ($node, $lhs, $rhs) = @_;
if( ! $lhs->evaluate($node)->to_boolean->value ) {
return XML::XPathEngine::Boolean->False;
}
else {
return $rhs->evaluate($node)->to_boolean;
}
}
sub op_match
{ my ($node, $lhs, $rhs) = @_;
my $lh_results = $lhs->evaluate($node);
my $rh_results = $rhs->evaluate($node);
my $rh_value = $rh_results->string_value;
if ($lh_results->isa('XML::XPathEngine::NodeSet') )
{ foreach my $lhnode ($lh_results->get_nodelist)
{ if ($lhnode->string_value=~ m/$rh_value/) # / is important here, regexp is / delimited
{ return XML::XPathEngine::Boolean->True; }
}
return XML::XPathEngine::Boolean->False;
}
else
{ return $lh_results->string_value =~ m/$rh_value/ ?
XML::XPathEngine::Boolean->True : XML::XPathEngine::Boolean->False;
}
}
sub op_not_match
{ my ($node, $lhs, $rhs) = @_;
my $lh_results = $lhs->evaluate($node);
my $rh_results = $rhs->evaluate($node);
my $rh_value = $rh_results->string_value;
if ($lh_results->isa('XML::XPathEngine::NodeSet') )
{ foreach my $lhnode ($lh_results->get_nodelist)
{ if ($lhnode->string_value!~ m/$rh_value/)
{ return XML::XPathEngine::Boolean->True; }
}
return XML::XPathEngine::Boolean->False;
}
else
{ return $lh_results->string_value !~ m/$rh_value/ ?
XML::XPathEngine::Boolean->True : XML::XPathEngine::Boolean->False;
}
}
sub op_equals {
my ($node, $lhs, $rhs) = @_;
my $lh_results = $lhs->evaluate($node);
my $rh_results = $rhs->evaluate($node);
if ($lh_results->isa('XML::XPathEngine::NodeSet') &&
$rh_results->isa('XML::XPathEngine::NodeSet')) {
# True if and only if there is a node in the
# first set and a node in the second set such
# that the result of performing the comparison
# on the string-values of the two nodes is true.
foreach my $lhnode ($lh_results->get_nodelist) {
foreach my $rhnode ($rh_results->get_nodelist) {
if ($lhnode->string_value eq $rhnode->string_value) {
return XML::XPathEngine::Boolean->True;
}
}
}
return XML::XPathEngine::Boolean->False;
}
elsif (($lh_results->isa('XML::XPathEngine::NodeSet') ||
$rh_results->isa('XML::XPathEngine::NodeSet')) &&
(!$lh_results->isa('XML::XPathEngine::NodeSet') ||
!$rh_results->isa('XML::XPathEngine::NodeSet'))) {
# (that says: one is a nodeset, and one is not a nodeset)
my ($nodeset, $other);
if ($lh_results->isa('XML::XPathEngine::NodeSet')) {
$nodeset = $lh_results;
$other = $rh_results;
}
else {
$nodeset = $rh_results;
$other = $lh_results;
}
# True if and only if there is a node in the
# nodeset such that the result of performing
# the comparison on <type>(string_value($node))
# is true.
if ($other->isa('XML::XPathEngine::Number')) {
foreach my $node ($nodeset->get_nodelist) {
if ($node->string_value == $other->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
elsif ($other->isa('XML::XPathEngine::Literal')) {
foreach my $node ($nodeset->get_nodelist) {
if ($node->string_value eq $other->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
elsif ($other->isa('XML::XPathEngine::Boolean')) {
if ($nodeset->to_boolean->value == $other->value) {
return XML::XPathEngine::Boolean->True;
}
}
return XML::XPathEngine::Boolean->False;
}
else { # Neither is a nodeset
if ($lh_results->isa('XML::XPathEngine::Boolean') ||
$rh_results->isa('XML::XPathEngine::Boolean')) {
# if either is a boolean
if ($lh_results->to_boolean->value == $rh_results->to_boolean->value) {
return XML::XPathEngine::Boolean->True;
}
return XML::XPathEngine::Boolean->False;
}
elsif ($lh_results->isa('XML::XPathEngine::Number') ||
$rh_results->isa('XML::XPathEngine::Number')) {
# if either is a number
local $^W; # 'number' might result in undef
if ($lh_results->to_number->value == $rh_results->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
return XML::XPathEngine::Boolean->False;
}
else {
if ($lh_results->to_literal->value eq $rh_results->to_literal->value) {
return XML::XPathEngine::Boolean->True;
}
return XML::XPathEngine::Boolean->False;
}
}
}
sub op_nequals {
my ($node, $lhs, $rhs) = @_;
if (op_equals($node, $lhs, $rhs)->value) {
return XML::XPathEngine::Boolean->False;
}
return XML::XPathEngine::Boolean->True;
}
sub op_le {
my ($node, $lhs, $rhs) = @_;
op_ge($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::XPathEngine::NodeSet') &&
$rh_results->isa('XML::XPathEngine::NodeSet')) {
foreach my $lhnode ($lh_results->get_nodelist) {
foreach my $rhnode ($rh_results->get_nodelist) {
my $lhNum = XML::XPathEngine::Number->new($lhnode->string_value);
my $rhNum = XML::XPathEngine::Number->new($rhnode->string_value);
if ($lhNum->value >= $rhNum->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
return XML::XPathEngine::Boolean->False;
}
elsif (($lh_results->isa('XML::XPathEngine::NodeSet') ||
$rh_results->isa('XML::XPathEngine::NodeSet')) &&
(!$lh_results->isa('XML::XPathEngine::NodeSet') ||
!$rh_results->isa('XML::XPathEngine::NodeSet'))) {
# (that says: one is a nodeset, and one is not a nodeset)
if ($lh_results->isa('XML::XPathEngine::NodeSet')) {
foreach my $node ($lh_results->get_nodelist) {
if ($node->to_number->value >= $rh_results->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
else {
foreach my $node ($rh_results->get_nodelist) {
if ( $lh_results->to_number->value >= $node->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
return XML::XPathEngine::Boolean->False;
}
else { # Neither is a nodeset
if ($lh_results->isa('XML::XPathEngine::Boolean') ||
$rh_results->isa('XML::XPathEngine::Boolean')) {
# if either is a boolean
if ($lh_results->to_boolean->to_number->value
>= $rh_results->to_boolean->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
else {
if ($lh_results->to_number->value >= $rh_results->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
return XML::XPathEngine::Boolean->False;
}
}
sub op_gt {
my ($node, $lhs, $rhs) = @_;
my $lh_results = $lhs->evaluate($node);
my $rh_results = $rhs->evaluate($node);
if ($lh_results->isa('XML::XPathEngine::NodeSet') &&
$rh_results->isa('XML::XPathEngine::NodeSet')) {
foreach my $lhnode ($lh_results->get_nodelist) {
foreach my $rhnode ($rh_results->get_nodelist) {
my $lhNum = XML::XPathEngine::Number->new($lhnode->string_value);
my $rhNum = XML::XPathEngine::Number->new($rhnode->string_value);
if ($lhNum->value > $rhNum->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
return XML::XPathEngine::Boolean->False;
}
elsif (($lh_results->isa('XML::XPathEngine::NodeSet') ||
$rh_results->isa('XML::XPathEngine::NodeSet')) &&
(!$lh_results->isa('XML::XPathEngine::NodeSet') ||
!$rh_results->isa('XML::XPathEngine::NodeSet'))) {
# (that says: one is a nodeset, and one is not a nodeset)
if ($lh_results->isa('XML::XPathEngine::NodeSet')) {
foreach my $node ($lh_results->get_nodelist) {
if ($node->to_number->value > $rh_results->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
else {
foreach my $node ($rh_results->get_nodelist) {
if ( $lh_results->to_number->value > $node->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
}
return XML::XPathEngine::Boolean->False;
}
else { # Neither is a nodeset
if ($lh_results->isa('XML::XPathEngine::Boolean') ||
$rh_results->isa('XML::XPathEngine::Boolean')) {
# if either is a boolean
if ($lh_results->to_boolean->value > $rh_results->to_boolean->value) {
return XML::XPathEngine::Boolean->True;
}
}
else {
if ($lh_results->to_number->value > $rh_results->to_number->value) {
return XML::XPathEngine::Boolean->True;
}
}
return XML::XPathEngine::Boolean->False;
}
}
sub op_lt {
my ($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
+
$rh_results->to_number->value
;
return XML::XPathEngine::Number->new($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
-
$rh_results->to_number->value
;
return XML::XPathEngine::Number->new($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::XPathEngine::Literal->new('Infinity');
}
return XML::XPathEngine::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
%
$rh_results->to_number->value
;
return XML::XPathEngine::Number->new($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
*
$rh_results->to_number->value
;
return XML::XPathEngine::Number->new($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::XPathEngine::NodeSet') &&
$rh_result->isa('XML::XPathEngine::NodeSet')) {
my %found;
my $results = XML::XPathEngine::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"};
}
return $results->sort->remove_duplicates;
}
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::XPathEngine::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::XPathEngine::Boolean')) {
if ($result->value) {
$newset->push($nodeset->get_node($i));
}
}
elsif ($result->isa('XML::XPathEngine::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;