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# $Id: Literal.pm,v 1.11 2001/03/16 11:10:08 matt Exp $
package XML::XPathEngine::Literal;
use XML::XPathEngine::Boolean;
use XML::XPathEngine::Number;
use strict;
use Carp;
use overload 
                '""'  => \&value,
                'cmp' => \&cmp;
sub new {
        my $class = shift;
        my ($string) = @_;
         
#       $string =~ s/"/"/g;
#       $string =~ s/'/'/g;
         
        bless \$string, $class;
}
sub as_string {
        my $self = shift;
        my $string = $$self;
        $string =~ s/'/'/g;
        return "'$string'";
}
sub as_xml {
    my $self = shift;
    my $string = $$self;
    return "<Literal>$string</Literal>\n";
}
sub value {
        my $self = shift; 
        $$self;
}
sub value_as_number {
        my $self = shift; 
 warn "numifying '", $$self, "' to '", +$$self, "'\n";       
        +$$self;
}
sub cmp {
        my $self = shift;
        my ($cmp, $swap) = @_;
        if ($swap) {
                return $cmp cmp $$self;
        }
        return $$self cmp $cmp;
}
sub evaluate {
        my $self = shift;
        $self;
}
sub to_boolean {
        my $self = shift;
        return (length($$self) > 0) ? XML::XPathEngine::Boolean->True : XML::XPathEngine::Boolean->False;
}
sub to_number { return XML::XPathEngine::Number->new($_[0]->value); }
sub to_literal { return $_[0]; }
sub string_value { return $_[0]->value; }
sub getChildNodes { croak "cannot get child nodes of a literal"; }
sub getAttributes { croak "cannot get attributes of a literal";  }
sub getParentNode { croak "cannot get parent node of a literal"; }
1;
__END__
HideShow 34 lines of Pod
=head1 NAME
XML::XPathEngine::Literal - Simple string values.
=head1 DESCRIPTION
In XPath terms a Literal is what we know as a string.
=head1 API
=head2 new($string)
Create a new Literal object with the value in $string. Note that &quot; and
&apos; will be converted to " and ' respectively. That is not part of the XPath
specification, but I consider it useful. Note though that you have to go
to extraordinary lengths in an XML template file (be it XSLT or whatever) to
make use of this:
        <xsl:value-of select="&quot;I'm feeling &amp;quot;sad&amp;quot;&quot;"/>
Which produces a Literal of:
        I'm feeling "sad"
=head2 value()
Also overloaded as stringification, simply returns the literal string value.
=head2 cmp($literal)
Returns the equivalent of perl's cmp operator against the given $literal.
=cut