=head1 NAME

XML::LibXML::PI - XML::LibXML Processing Instructions

=head1 SYNOPSIS

  $pinode->setData( $data_string );
  $pinode->setData( name=>string_value [...] );


=head1 DESCRIPTION

Processing instructions are implemented with XML::LibXML with read and write
access. The PI data is the PI without the PI target (as specified in XML 1.0
[17]) as a string. This string can be accessed with getData as implemented in
XML::LibXML::Node.

The write access is aware about the fact, that many processing instructions
have attribute like data. Therefore setData() provides besides the DOM spec
conform Interface to pass a set of named parameter. So the code segment

  my $pi = $dom->createProcessingInstruction("abc");
  $pi->setData(foo=>'bar', foobar=>'foobar');
  $dom->appendChild( $pi );

will result the following PI in the DOM:

  <?abc foo="bar" foobar="foobar"?>

Which is how it is specified in the DOM specification. This three step
interface creates temporary a node in perl space. This can be avoided while
using the insertProcessingInstruction() method. Instead of the three calls
described above, the call

  $dom->insertProcessingInstruction("abc",'foo="bar" foobar="foobar"');

will have the same result as above.

XML::LibXML::PI's implementation of setData() differs a bit from the the
standard version as available in XML::LibXML::Node():

=over 4

=item B<setData>

  $pinode->setData( $data_string );
  $pinode->setData( name=>string_value [...] );

This method allows to change the content data of a PI. Additionaly to the
interface specified for DOM Level2, the method provides a named parameter
interface to set the data. This parameterlist is converted into a string before
it is appended to the PI.



=back

=head1 AUTHORS

Matt Sergeant, 
Christian Glahn, 
=head1 VERSION

1.56

=head1 COPYRIGHT

2001-2002, AxKit.com Ltd; 2001-2003 Christian Glahn, All rights reserved.

=cut
