=head1 NAME

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

=head1 SYNOPSIS



  use XML::LibXML;
  # Only methods specific to Processing Instruction nodes are listed here,
  # see XML::LibXML::Node manpage for other methods

  $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 L<<<<<< 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.

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

=over 4

=item setData

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

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



=back

=head1 AUTHORS

Matt Sergeant,
Christian Glahn,
Petr Pajas


=head1 VERSION

2.0018

=head1 COPYRIGHT

2001-2007, AxKit.com Ltd.

2002-2006, Christian Glahn.

2006-2009, Petr Pajas.

=cut
