use strict;
use warnings;
 
 
sub xdefined  {
  my $ref=shift;
  my $type;
  while ( my $key=shift) {
    $type= ref($ref);
    if    ( $type eq "HASH"  ) {
      return unless defined $ref->{$key};
      $ref=$ref->{$key}
    }
    elsif ( $type eq "ARRAY" ) {
      return unless  defined $ref->[$key];
      $ref=$ref->[$key]
    }
    else                       # no reference
      { return }; 
  }
  return defined $ref;
}
 
 
my $h->{a}->[2]->{c}=0;
$\="\n";
$,=":";
print 5, xdefined($h,"a",2,"c",4,"e");
print 4, xdefined($h,"a",2,"c",4);
print 3, xdefined($h,"a",2,"c");
print 2, xdefined($h,"a",2);
print 1, xdefined($h,"a");
print 0, xdefined($h);

##</code><code>##

5
4
3:1
2:1
1:1
0:1