[Parseperl-discuss] Bug: undef location for empty list

[Chris D. <ch...@ch...>]

Adam et al.,

I've discovered that an empty list falsely returns undef from its  
location() method.  Consider this code snippet: "()" which yields a  
tree like this:

   PPI::Document
     PPI::Structure::List          ( ... )

If I try to access the location of that List, I get undef.  For example:

   use Data::Dumper;
   use PPI::Document;
   $d = PPI::Document->new(\"()");
   $d->index_locations;
   print Dumper($d->find("PPI::Structure::List")->[0]->location);

$VAR1 = undef;

This should instead do something like this:

   print Dumper($d->find("PPI::Structure::List")->[0]->{start}- 
 >location);

$VAR1 = [1,1,1];


The reason is that the List has no children, and thus no PPI::Token  
instances to hold a location.  Instead, List nodes have "start" and  
"finish" properties that hold their bracket tokens.

To solve this, I propose that the PPI::Structure::List class  
overrides location() to return the location of its start token.  If  
this sounds sensible, I'd be happy to implement it.

Chris
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