change setHandlers XML::Parser

[etlamar]

Can anyone help me change Handlers in XML::Parser?

Code excerpt is as follows:

#!/usr/bin/perl -w
use strict;
use XML::Parser;

open (FILEA, "File.txt");
my $parser = XML::Parser->new();        
$parser->setHandlers(Start => \&handle_start,
                    Char => \&handle_char,
                    End => \&handle_end1,
                    Final => \&final1);
                                            
$parser-parsefile('File2.txt');
my $char_array_ref;
my @end_array;

sub handle_start{
my $e = shift;
my $start_element = shift;
if ($start_element eq 'coordinates'){print "hello.\n";
    $parser->setHandlers(Char => \&coord);
    }
 }
sub handle_char{
my $e = shift;
print "HELLO There\n.";
}

sub coord{
my $e = shift;
print "hello again.\n";
}

Use of print commands serve as a test to see which subroutines are called on Char events.

I never see "hello again" printed to the screen.

The Expat documentation suggests that you can change a handler conditionally as I am trying to do.

But I cannot seem to get it to work.

Can anyone point me in the right direction?

I would be very much obliged.

Thanks

[Anonymous Monk]

forget about XML::Parser, use XML::Twig, see http://xmltwig.org/

see XML::Twig basic handlers, Re: XML::Simple usage question (steriods), Re: XML-Twig paste, http://xmltwig.org/, XML::Twig newbie question, Re^2: finding XPATH for any node in a XML file, Re: trouble,, need help! (parsing apache jmeter xml, preparing html report), Re: XML::Twig n00b , Re^3: parse xml and store data in array of hashesh

[Jenda]

XML::Parser is a little too low-level. What is it you are trying to achieve?

[etlamar]

Thanks, Jenda, and Anonymous Monk, I am trying to parse through a huge kml file that contains longitude and latitude coordinates for census blocks and pull out only those long and lat coords that pertain to certain blocks within a subset of census tracts. I will have CDATA information to parse through to get the tract and block numbers, but right now I am just trying to test code on pulling out the long and lat coordinates that are denoted by a <coordinates> tag in the xml.

In other words, right now, I want to extract information only if the Start handler indicates a <coordinates> tag. That's why I am looking for a way to conditionally switch to a different handler.

Sorry for the long-winded answer.

Hope this helps.

XML::Twig looks interesting, but I was hoping to stick with a more SAX-like parser rather than DOM-like or pull-parser like.

Would you also suggest XML::Twig?

Thanks again.

[Jenda]

You can ask XML::Twig to give you just the tag(s) you are interested in (twig_root) and handle them by a custom subroutine. Or you can have a look at XML::Rules and basically do the same. Or if you were so inclined use XML::LibXML::SAX.

[Anonymous Monk]

XML::Twig looks interesting, but I was hoping to stick with a more SAX-like parser rather than DOM-like or pull-parser like.

XML::Twig is super flexible, its SAX+DOM or SAX or DOM.

Rarely do you want to use the SAX feature alone, mostly its SAX+DOM (SAX+TWIG, only a little piece of DOM).

Re: XML::Twig n00b

$ perl
use XML::Twig ;
XML::Twig->new(
  twig_handlers => {
    'coordinates' => sub {
      print $_->xpath, "\n";
      print $_->trimmed_text, "\n\n";
    },
  },
)->xparse( "somefile.xml" );
__END__
/on/no/coordinates
ro

/on/ma/to/peia/coordinates
sham

/on/coordinates
bo

/on/coordinates[2]
<b>Asin</b> (I) - Biography


$ cat somefile.xml
<on>
<no><coordinates>ro</coordinates></no>
<ma><to><peia><coordinates>sham</coordinates></peia></to></ma>
<coordinates>bo</coordinates>
<coordinates><![CDATA[<b>Asin</b> (I) - Biography]]></coordinates>
</on>