Got it. In that case I think the -fold version is going to be harder to use, because the five procedures will often have to share mutable data.  Just generating the JSON objects and dispatching on their type (JSON simple value or one of the symbols object-start etc.) seems much more straightforward.

On Tue, Feb 11, 2020 at 4:49 PM Amirouche Boubekki <xxxxxx@gmail.com> wrote:
Le mar. 11 févr. 2020 à 22:43, John Cowan <xxxxxx@ccil.org> a écrit :
>
>
>
> On Fri, Feb 7, 2020 at 12:27 PM Amirouche Boubekki <xxxxxx@gmail.com> wrote:
>
>>
>> json-fold signature is different from generator-fold:
>>
>>   (json-fold proc object-start object-end array-start array-end seed events)
>>
>> where EVENTS is a generator.
>
>
> What are these arguments object-start/end and array-start/end?  Are they procedures or what?
>

They are procedure


--
Amirouche ~ https://hyper.dev