[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: help with guile-json inconsistencies

From: swedebugia
Subject: Re: help with guile-json inconsistencies
Date: Mon, 10 Dec 2018 09:12:47 +0100

On 2018-12-10 08:27, Aleix Conchillo Flaqué wrote:
On Sun, Dec 9, 2018 at 10:33 PM Aleix Conchillo Flaqué
<address@hidden> wrote:

On Sun, Dec 9, 2018 at 2:56 AM Aleix Conchillo Flaqué
<address@hidden> wrote:

Hi guilers,

a new guile-json issue came to me recently:

I don't really have a solution yet on how to solve this, so I would
love some advice. The issue is that one can do:

   (scm->json '(1 2 3)) which returns [1,2,3]

however, if you do:

   (scm->json '((1 2 3)) it returns {"1":[2,3]} but one would probably
expect [[1,2,3]]
   (scm->json '((1 2 3) (4 5 6)) it returns {"1":[2,3], "4":[5,6]} but
one would probably expect [[1,2,3], [4,5,6]]

I guess the first question is, does everyone else feel the same way
about the return value?

The problem is that there's a function that checks if something is an
alist by basically checking if it's a pair? recursively and if so, it
builds a json object.

Just to clarify, the problem is not when parsing JSON to scheme data
types, this is fine as internally guile-json uses hash tables and
lists properly.

The problem is with going from scheme to json. For convenience,
guile-json doesn't expect a hash table from the user, instead it tries
to guess what's a list and what's an alist however, that seems not
really distinguishable. That is, there's no way to tell if '((1 2)) is
[[1, 2]] or {"1" : [2]} or  {"1" : "2"}.

I guess going back to a macro approach for these type of cases would
help (even though I had the same problem with my initial macro).

Answering myself again. Re-adding the macro fixes the issue, but with
a breaking change.

(scm->json '(1 2 3))
       -> [1,2,3]

(scm->json '((1 2 3) (4 5 6)))
       -> [[1,2,3],[4,5,6]]

(scm->json (json (object ("key1" "value1") ("key2" (1 2 3)))))
       -> {"key2":[1,2,3],"key1":"value1"}

(scm->json `((1 2 3) ,(json (object (4 5)))))
       -> [[1,2,3],{"4":5}]

So, the (json) macro is only needed to specify JSON objects, otherwise
you can use scheme types directly (and lists are always arrays).

Nice to hear you solved it :)

Both Guix and guile-wikidata use guile-json but only from json->scm and that works flawlessly. Thanks for creating and maintaining this lib.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]