& XSLT On 23 Aug 2004, at 20:29, Kevin Old wrote:

>  Hello everyone,
> 
>  I'm new to parsing XML files.  I've got a somewhat working attempt,
>  but keep getting errors when certain elements are undefined.
> 
>  Can't call method "as_text" on an undefined value at ./xmltreebuild.pl 
>  line 33.

Believe the error message! Line 33 is:

  $tmp[11] = $prod-> find_by_tag_name('runtime')->as_text;

So the find_by_tag_name is returning undef, rather than an object that 
has an as_text method. Its not finding runtime, because in the xml its 
spelled run-time.

But if you may or may not find a match, you'll have to check:

   if ( $elem = $prod-> find_by_tag_name('run-time') ) {
     $tpm[11] = $elem-> as_text;
   }

EasyTree or another package may give you a nicer way of doing this that 
lots of conditionals in your code.

Richard