Re: [PATCH] Accept plists when serializing and parsing JSON

[Yuri Khan <yurivkhan@gmail.com>]

On Wed, May 30, 2018 at 5:31 AM João Távora <joaotavora@gmail.com> wrote:

> On Tue, May 29, 2018, 22:21 Philipp Stephani <p.stephani2@gmail.com>
wrote:

>> Please don't add global state to json.c. It's a low-level library that
shouldn't rely on global state (and global state should generally be
avoided in libraries). Not having global state was one of my explicit
design goals for json.c

> Well, it's not really "global state" in the sense I believe you're
talking about, because no part of the library is maintaining any state in
global variables -- it's read-only from json.c.

I think the objection to global state (or a global setting, as the case may
be) can be illustrated with the following scenario.

* Consider two independent Elisp packages ‘foo’ and ‘bar’, both of which
want to use the JSON library.
* ‘foo’ wants plists while ‘bar’ wants alists.
* ‘foo’ has a hook. The user adds to that hook a function that invokes
‘bar’.
* Result (after ironing out all bugs related to shared state): Every call
to the JSON library has to be wrapped in a (let ((json-serialize-use-plists
…)) …), which is more cumbersome than just passing an argument to a
function.