Question

I only want to parse an interested element of xml (e.g. see below: class element with name equals to math) and I want to stop once the first element hitting this condition is parsed. (since There is only one class whose name is math, it is unnecessary to continue once the element is already found).

However, if I implement as follows, the code continues to read the whole file after it found the element i am interested (the xml file is very long so it takes long time). my question is how to stop it once the first class element with name = math is parsed?


my $twig = new XML::Twig(TwigRoots => {"class[\@name='math']" => \&class});
$twig->parsefile( shift @ARGV );

besides, I also want to delete this class from xml file (not only from memory) after it is parsed so that next time when parsing a class with other names, the class element will not be parsed. Is it possible to do that?

Answer 1

It seems what you’re looking for are XML::Twig’s finish_print and finish_now :

finish_print

Stops twig processing, flush the twig and proceed to finish printing
the document as fast as possible. Use
this method when modifying a document
and the modification is done.

finish_now

Stops twig processing, does not finish parsing the document (which
could actually be not well-formed
after the point where finish_now is
called). Execution resumes after the
Lparse> or parsefile call. The content
of the twig is what has been parsed so
far (all open elements at the time
finish_now is called are considered
closed).