bug#15097: 24.3.50; json.el can't encode lists of lists

[Glenn Morris]

Rolando Pereira wrote:

> The function `json-encode' can't encode a list thats composed only of other
> lists, i.e. the following doesn't work:
>
>     (json-encode '((1 2 3))) => Error: (json-key-format 1)
[...]
> (ert-should (string= (json-encode '((1 2 3))) "[[1,2,3]]")) ; doesn't work

I have no idea what this stuff is supposed to do, but by inspection it
treats such arguments as alists and requires that the key be encodable
as a string. Eg this works

(json-encode '((a 2 3)))   ->    "{\"a\":[2, 3]}"

Your example fails because 1 is encoded as 1, not "1".

Should the answer be "{\"1\":[2, 3]} or "[[1,2,3]]"?