Fellow Monks, --
I'm playing with a directory parsing based on example 4.3 from HOP v.1:

### Iterate.pl
use strict;
use warnings;
use Iterator_Utils;
# ---------------------------------------------------------
sub interesting_files {
 my $is_interesting = shift;
  my @queue = @_;
  return Iterator {
    while (@queue) {
      my $file = shift @queue;
      if (-d $file) { 
        opendir my $dh, $file or next;
        my @newfiles = grep {$_ ne "." && $_ ne ".."} readdir $dh;
        push @queue, map "$file/$_", @newfiles;
      }
      return $file if $is_interesting->($file);
    } 
    return;
  };
}
# --------------------------------------------------------
sub $is_WrappedXml {
	my $file = shift;
	return 1 if $file =~ /WrappedXml.{0,5}\.xml/i;
	return;
}
# --------------------------------------------------------
# MAIN
my $WrappedXml_file = interesting_files(\$is_WrappedXml, '.');
while (defined($file = NEXTVAL($WrappedXml_file))) 
	print $file;
}

where

### Iterator_Utils.pm
package Iterator_Utils;
use base Exporter;
@EXPORT_OK = qw(NEXTVAL Iterator);
%EXPORT_TAGS = ('all' => \@EXPORT_OK);

sub NEXTVAL { $_[0]->() }
sub Iterator (&) { return $_[0] }
1;

When running program Iterate.pl i get the error:
C:\tmp>Iterate
Illegal declaration of anonymous subroutine at
C:\tmp\Iterate.pl line 26.

Any ideas why the Iterator {...} construct is illegal in this context ??

Best regards,
Allan Dystrup