Thank you for your hints.

If $r is a hash ref, then $$r is a hash, then $$r{$k} is a value in that hash. This is of course the matter of style only.

Yes -- I'm doing deep recursion. Example of use below: 

# echo '{"alfa": { "beta": null, "teata": null, "adfa": null, "n": {},
+ "ixi": {}, "marr": [1, 2] } }' | ./tidyup_json
{
   "alfa" : {
      "marr" : [
         1,
         2
      ]
   }
}


# echo '{"alfa": { "beta": null, "teata": null, "adfa": null, "n": {},
+ "ixi": {}, "marr": [null, null] } }' | ./tidyup_json
null



# echo '{"alfa": { "beta": null, "teata": null, "adfa": null, "n": {},
+ "ixi": {}, "marr": [null, null, 3] } }' | ./tidyup_json
{
   "alfa" : {
      "marr" : [
         3
      ]
   }
}


# echo '{"alfa": { "beta": { "gamma" : 3 } } }' | ./tidyup_json
{
   "alfa" : {
      "beta" : {
         "gamma" : 3
      }
   }
}


# echo '{"alfa": { "beta": { "gamma" : {} } } }' | ./tidyup_json
null



# echo '{"alfa": { "beta": { "gamma" : {} }, "nth": 9 } }' | ./tidyup_
+json
{
   "alfa" : {
      "nth" : 9
   }
}

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

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