sjson.NULL is missing

[fikin]

Expected behavior

Decoded null values are represented as "userdata: (nil)", which according doc should be identical to sjson.NULL constant.

Actual behavior

it appears sjson.NULL is missing completely from module exports ;)

Test code

Provide a Minimal, Complete, and Verifiable example which will reproduce the problem.

> =sjson.decode('[null]')
table: 0x3fff5040
> =sjson.decode('[null]')[1]
userdata: (nil)
> =sjson.decode('[null]')[1]==sjson.NULL
false
> =type(sjson.NULL)
nil

NodeMCU startup banner

NodeMCU 3.0.0.0
branch: lua53
commit: 6fdfc48eeea5da86db22d2e469cc9d8885f1ae69
release: 3.0.0-release_20211229 +12
release DTS: 202211122042
SSL: false
build type: float
LFS: 0x20000 bytes total capacity
modules: adc,bit,crypto,encoder,file,gpio,i2c,net,node,rtcmem,rtctime,sjson,sntp,spi,tmr,uart,wifi
build 2022-11-20 15:14 powered by Lua 5.3.5 on SDK 3.0.1-dev(fce080e)

Hardware

WeMos D1

[marcelstoer]

@pjsg I vaguely remember you fixed something like this in the past, correct?

[fikin]

@pjsg : i wonder would you like to give me some implementation suggestions and i can add a NULL constant to the module?

form what i've seen so far, the workaround is to json decode '{"a":null}' and use that. but there should be some constant already in the code to act as same, isn't there?

[pjsg]

Hmm. The problem is that the null value is actually on a per encoder basis. This feels broken to me and I think that there ought to be a sjson.NULL that has a specific value. I suspect that you need a row like LROT_LUDENTRY(NULL, JSON_NULL) in the block that begins LROT_BEGIN(sjson, NULL, 0). But I'm not quite sure how the JSON_NULL should be defined.