Awesome description, Jacob! It’s been some time since I’ve had to be thinking at these lower levels, so I just need some oil on my mind. I really appreciate the details from you and Jeff. You both have saved me much time and confusion.
Regards From: jacob <jacobgilb...@protonmail.com> Sent: Thursday, June 30, 2022 9:43 AM To: Jeff S <e070...@hotmail.com> Cc: Jeff Long <willco...@gmail.com>; discuss-gnuradio@gnu.org Subject: RE: Is PMT_NIL a Valid Dictionary? Hi Jeff Just to help clarify this a bit, PMT_NIL is a valid PMT object (not to be confused with null) PMT Dictionary type objects are nested pairs, and empty dictionary type objects (from pmt::make_dict() for example) are literally represented as a single PMT_NIL object under the hood, so this is specifically checked for and passes is_dict(). As dictionary items are added, the base dictionary (or empty dict / PMT_NIL object) gets paired with added key-value pairs. Its not the best possible implementation, but has served GR for some time. PMTs are getting a modernization / overhaul soon. The is_pdu() check should abstract that oddness a bit. Jacob ------- Original Message ------- On Thursday, June 30th, 2022 at 7:12 AM, Jeff S <e070...@hotmail.com<mailto:e070...@hotmail.com>> wrote: Cool. I appreciate the clarification. I had always taken an empty dictionary as a dictionary object without data, and a NIL as not an object, and the two were different. This helps my PDU checking. And I also found the update I missed which added is_pdu(), which simplifies some of my checking. So, even better! Thanks for the help, Jeff From: Jeff Long <willco...@gmail.com<mailto:willco...@gmail.com>> Sent: Thursday, June 30, 2022 8:02 AM To: Jeff S <e070...@hotmail.com<mailto:e070...@hotmail.com>> Cc: discuss-gnuradio@gnu.org<mailto:discuss-gnuradio@gnu.org> Subject: Re: Is PMT_NIL a Valid Dictionary? Yes, an empty dict is NIL, so that is (confusingly) valid. On Thu, Jun 30, 2022 at 7:05 AM Jeff S <e070...@hotmail.com<mailto:e070...@hotmail.com>> wrote: GNU Radio Version: v3.9.6.0-23-ge3506b13 I was writing a QA test and decided to try, self.assertTrue(pmt.is_dict(pmt.PMT_NIL)) and it passes. I was just wondering if pmt.PMT_NIL is considered a valid dictionary object, as opposed to, my_dict = pmt.make_dict() self.assertTrue(pmt.is_dict(my_dict)) Just trying to get a better understanding and couldn’t find an answer. Regards, Jeff
