json <-> erlang mapping (null is undefined)

[kostiushkin]

Displaying json null as an atom null in erlang incorrectly, in Erlang null is atom undefined

[talentdeficit]

i think there's a (subtle) difference between null and undefined and am not in favour of equating them, but i'm open to having my mind changed

my main concern is that proplists use undefined to represent keys that are not present, while keys that have value null ARE present

[kostiushkin]

In fact, undefined is used not only in proplists, but also in the records, and in many other modules.

In erlang records undefined used in same context as null in json.

[talentdeficit]

right, but proplists are relevant because they are the default representation of jaon objects when decoded. if json null is mapped to erlang undefined, the proplists module can no longer distinguish between "{"key": null}" and "{}". while this is probably harmless, it does concern me

[kostiushkin]

I'm sure, this is not only harmless but even useful.

[viplifes]

null is not undefined. So do not.

[kostiushkin]

I am glad to agree, but where are the arguments?

My arguments were higher, and they are based on the fact that in erlang no null but there are undefined.

[kostiushkin]

As I discovered, some erlang applications really use atom null, although I still believe it is wrong, the issue no longer seems so simple.