Re^3: XML::Twig - How do I check to see if an element exists in root?

# specify twig_handlers (see the XML::Twig documentation)
twig_handlers => 
   { # create a new hash-ref
       map { # transform a list into a new list 
             # create a name / subroutine pair
             $_ => sub {
                # when the subroutine is called
                # get the element name from $_->name()
                # and increase it's count entry in %found
                #
                # note: $_ is set by XML::Twig when the sub is called
                $found{$_->name()}++ 
             }; 
       } @nodes # for each element in @nodes
   }
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See also map.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

Comment on Re^3: XML::Twig - How do I check to see if an element exists in root? Download Code

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Re^4: XML::Twig - How do I check to see if an element exists in root? by dbmathis (Scribe) on Jul 09, 2007 at 17:15 UTC
So I am assuming that the first $_ gets populated buy 'map' with the values from 'node'? What about the $_ in the hash found? Where does it get its value from? I searched for name() on the CPAN page for XML Parser and XML Twig and I could not find it? Where is the subroutine name() coming from. This code works but I am still abit confused on the mechanics of it.	[reply]
Re^5: XML::Twig - How do I check to see if an element exists in root? by Joost (Canon) on Jul 14, 2007 at 00:04 UTC
Sorry for the late reply. Anyway: map works by calling a codeblock for each element of the supplied list and passes the element as $_. (click the link to see the official docs for map) name() is mentioned on the XML::Twig documentation, in the (very long and not very well structured) section called METHODS. It just returns the "tag-name" for an XML::Elt, i.e. for `<tagname attr="value" att2="value2"/>` it returns the string "tagname". The code I supplied basically creates an anonymous subroutine, or code block, for each tag-name you're interested in and XML::Twig will call that subroutine whenever it finds a tag with that tag-name, passing an object (update: as $_ - which is generally considered poor style, but makes for short and possibly more readable code) that represents that tag (and you can call ->name() on that object to retrieve the tag name) "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re^6: XML::Twig - How do I check to see if an element exists in root? by dbmathis (Scribe) on Jul 21, 2007 at 16:25 UTC
Thanks for your help.	[reply]