Re: Which newsgroup for json parsing?

On 2024-05-16 18:01:15 +0000, Josef Möllers said:

On 16.05.24 18:27, Mikko wrote:

On 2024-05-08 13:04:56 +0000, Josef Möllers said:
 

Hi all,
 I am trying to parse a json string received through MQTT from a "Shelly Plug S", e.g.
{"id":0, "source":"button", "output":true, "apower":0.0, "voltage":237.9, "current":0.000, "aenergy":{"total":0.000,"by_minute":[0.000,0.000,0.000],"minute_ts":1715172119},"temperature":{"tC":41.1, "tF":106.0}}
 I am trying to use libjson-glib but I can't figure out what to use as the first argument to json_gobject_from_data()!
I am also looking at libjson-c but cannot find any examples that could guide me.
 Thanks in advance,

 Sometimes it is easier to make a parser than to use an existing one.
In this case I might try LEX.
 

 Sorry to be nitpicking, but lex is a "lexical analyzer" aka a "scanner", it can only recognize tokens, eg the brackets, quotes, identifiers etc, but not structures.
"yacc" (or its "bison" equivalent" would be a parser but definitely too heavy.
 What one could do would be to use LEX to recognize the tokens and the write a recursive descent parser in plain C.

As YACC is too heavy I would use only LEX and do with C what LEX alone
cannot do. I havn't often done so but when I did I got what I wanted.
For JSON parsing a stack of partly parsed objets and arrays is sufficient
in addition to what LEX gives, so the C code can be kept simple. LEX
can put C fragment to the right place in the final code.
If a generic parser is not needed but only a parser with specific structures
known in advance the result of parsing can be delivered in a form that is
easier to use than a result from a generic JSON parser. In addition, the
LEXä+C code can simpler in some sense although more complicated in another
sense.

But, as I wrote in another posting, I have switched to libjson-c5 and the code works fine.

That the code works fine is the most important aspect.
--
Mikko