Re: Passing data to XML::Twig twig_roots callbacks....?

From: Dustin Suchter <[email protected]>
> So this code runs, but obviously doesn't pass my data. It loops the
> expected number of times, given the XML it is parsing:
> 
> sub get_grandchild_info {
>   my hash_ref = shift();
>   return sub {
>     my ($twig, $element) = @_;
>     #blah blah, do something print-y here
>   }
> }
> 
> my $xmltwigobj = XML::Twig->new(
>      twig_roots => {
>        'Information/Child/Grandchild' =>
>        get_grandchild_info,
>      }
> );
> 
> If I change the object instantiation code to what immediately
> follows, my subroutine executes precisely 1 time only:
> 
> sub get_grandchild_info {
>   my hash_ref = shift();
>   return sub {
>     my ($twig, $element) = @_;
>     #blah blah, do something print-y here
>   }
> }
> 
> my $xmltwigobj = XML::Twig->new(
>      twig_roots => {
>        'Information/Child/Grandchild' =>
>        get_grandchild_info(),
>      }
> );
> 
> And finally this version does the same thing, executing just the
> first time the subroutine is "instantiated" - a term I'll use
> lightly since I believe this is technically a closure-utilizing
> callback, not an object:
> 
> sub get_grandchild_info {
>   my hash_ref = shift();
>   return sub {
>     my ($twig, $element) = @_;
>     #blah blah, do something print-y here
>   }
> }
> 
> my $xmltwigobj = XML::Twig->new(
>      twig_roots => {
>        'Information/Child/Grandchild' =>
>        get_grandchild_info($self),
>      }
> );
> 
> I'm guessing there's something wrong with the prototype for my
> subroutine so $smltwigobj isn't really connecting with
> get_granchild_info when I change the number of args... the question
> is (a) why? and (b) how to fix that?

Without the actual code I can't tell. The last version (after fixig 
the syntax) should be right. The get_grandchild_info() should be 
called just once (when the $xmltwigobj is being created), but the 
closure returned by that subroutine should be called several times.

Please create a complete script and example XML. 

Jenda
===== [email protected] === http://Jenda.Krynicky.cz =====
When it comes to wine, women and song, wizards are allowed 
to get drunk and croon as much as they like.
	-- Terry Pratchett in Sourcery

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