>Is there more elegant way to handle it?

The way you have it right now, as a recursive depth first (looks like) traversal of an abritrarily complex data structure, I am going to say no. 

$_[0] = undef if 
        (ref $r eq "HASH" && ! %$r) or
        (ref $r eq "ARRAY" && ! @$r);

[download]
The above code is simply the base case of your recursion, what allows it to unwind the call stack.

What is tripping me up is that I have no immediate idea what $$r{$k} is doing - is that some sort of generic reference? Double dollar signs are generally a red flag for me, so I can't really recognize when they might be doing something useful.

Do you have a snippet of JSON to share? I am really curious about your method of traversing the hash. I feel like there is a module on CPAN that allows more idiomatic interactions with your datastructure you call, $json.

Note: I always think myself later when I don't mix up what is $json (a string) and what is the deserialized reference: 

my $reference_from_json = JSON->new->allow_nonref->relaxed->decode(do 
+{ local $/; <STDIN>; }); 
tidyup_json($refrence_from_json); 

print JSON->new->pretty->allow_nonref->canonical->encode($reference_fr
+om_json);

[download]
>Beware that "true" and "false" jsonish data are references to blessed hashes.

Which one, JSON::PP::Boolean? In JSON::PP::Boolean::value_to_json, I see: 

        elsif( blessed($value) and  $value->isa('JSON::PP::Boolean') )
+{
            return $$value == 1 ? 'true' : 'false';
        }

[download]
Indicates to me some implicit recognition of a TO_JSON method that the family of JSON modules support for serializing complex data structures containing blessed references into stringified JSON form.

In reply to Re: Tidy up json from nulls, empty arrays and hashes by perlfan
in thread Tidy up json from nulls, empty arrays and hashes by leszekdubiel

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