Re: Standards for JSON decoders

[Sean Conner <sean@...>]

It was thus said that the Great Dirk Laurie once stated:
> 2017-06-15 17:42 GMT+02:00 Sean Conner <sean@conman.org>:
> >
> > It was thus said that the Great Dirk Laurie once stated:
> > > Is the Lua representation of JSON reasonably standard across decoders
> > > by now? The one I use [1] translates integers to integers; floats to floats;
> > > strings to strings; arrays and objects to tables, distinguished by
> > > their metatables. There is one metatable for all JSON objects and
> > > another for all JSON arrays. Those metatables are not functional,
> > > they merely contain fields that identify to which JSON type the table
> > > corresponds.
> > >
> > > Do other JSON decoders do this differently?
> >
> >   For Lua 5.3, my own JSON decoder [2] returns integers as integers, floats
> > as floats and arrays and objects as tables sans a metatable.
> 
> That decodes JSON '[]' and JSON '{}' to inditinguishable Lua tables.
> I presume you only decode, not encode too?

  JSON decode only.  When I wrote the CBOR module [1][2], I used a huristic
to encode a Lua table as an array or a map (what JSON calls an object) [3]. 
Of course that can be overriden by the user with supplying a __tocbor()
metamethod.

  For decoding, I didn't bother with distinguishing a map vs. an
array---you'll get a Lua table and it's up to the user to know if it should
be a map or an array (that was my thought anyway).  And again, if you want
such a distinction, you can do it (by supplying an optional conversion
function called during the decoding process).

  -spc (Who likes CBOR over JSON)

[1]	https://github.com/spc476/CBOR

[2]	Think of CBOR as a superset of JSON.  It allows semantic tagging of
	data, which allows for things like dates (a few formats) or even
	circular references (so you can encode a table defined as "x = {}
	x[x] = x").

[3]	https://github.com/spc476/CBOR/blob/cb11a9c32f742a8b369a9b8d07bea9a2fa68879a/cbor.lua#L1303