Re: [Json] Proposal: JSON text sequence MIME type and Proposed Standard

Nico Williams <nico@cryptonector.com> Wed, 12 March 2014 05:03 UTC

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Date: Wed, 12 Mar 2014 00:03:10 -0500
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From: Nico Williams <nico@cryptonector.com>
To: Tim Bray <tbray@textuality.com>
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Cc: Nico Williams <nico@cryptonector.com>, "Manger, James" <James.H.Manger@team.telstra.com>, "json@ietf.org" <json@ietf.org>
Subject: Re: [Json] Proposal: JSON text sequence MIME type and Proposed Standard
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On Tuesday, March 11, 2014, Tim Bray <tbray@textuality.com> wrote:

> Except for, in this kind of application, I think it’s really foolish to
> write out anything but objects. In which case you could theoretically have
> no separators.
>

I don't think that's going to change running code.  Indeed, this is about
writing down what's actually been implemented and deployed that doesn't
suffer from ambiguities.  You also seem to want all JSON texts to be
objects, but wanting ain't getting :)


> I lean to \s+ because as soon as you see the first char, you’re at the
> start of the next legal JSON text.
>

The separator can be whitespace.  It can be any whitespace recognized as
such in the JSON ABNF.  It could be a subset of that.  It also could be any
character or string of them that can't start a JSON value's encoding.
 Since in practice existing apps use whitespace, we should use whitespace.
 If other apps can be found using ", " or "," or whatever, we might be able
to require parser support for all of them or else define multiple MIME
types.

Since any contiguous sequence of separators cannot yoeld an empty JSON text
(since we've not defined the meaning of such a thing), And given what apps
like jq apps do, I think any number of contiguous separators must be
equivalent to just one.

Also, it's much better to follow a text with a separator than to only
precede them with a separator.  This is so parsers needn't wait for the
next text or EOF before yielding a true/false/null/numeric top-level value.

Finally, I think we should require that sequence parsers be able to handle
missing separators where they aren't necessary to disambiguate texts.

Nico
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