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
) 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");
$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
will have the same result as above.
XML::LibXML::PIs implementation of setData() documented below differs a bit from the standard
version as available in XML::LibXML::Node:
$pinode->setData( $data_string );
$pinode->setData( name=>string_value [...] );
This method allows one 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.