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Re: [Json] Unpaired surrogates in JSON strings

Tim Bray <tbray@textuality.com> Thu, 06 June 2013 00:31 UTC

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Date: Wed, 05 Jun 2013 17:18:50 -0700
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From: Tim Bray <tbray@textuality.com>
To: Paul Hoffman <paul.hoffman@vpnc.org>
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Cc: Douglas Crockford <douglas@crockford.com>, "json@ietf.org" <json@ietf.org>
Subject: Re: [Json] Unpaired surrogates in JSON strings
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In section 2.5 of 4627, a reasonable reading of the text clearly disallows
unpaired surrogates, because the discussion is exclusively of characters,
which surrogates aren’t; they are code points, but there are no characters
that have those code points. From the introduction: “A string is a sequence
of zero or more Unicode characters”. Case closed.

A loose reading of the BNF probably allows naked surrogates if you ignore
what the text says.

I think anyone who’s delivering those codepoints is already in violation of
4627, and I don’t think we should retroactively forgive those sins.

-T


On Wed, Jun 5, 2013 at 4:55 PM, Paul Hoffman <paul.hoffman@vpnc.org> wrote:

> On Jun 5, 2013, at 11:57 AM, Douglas Crockford <douglas@crockford.com>
> wrote:
>
> > On 6/5/2013 11:47 AM, John Cowan wrote:
> >> Douglas Crockford scripsit:
> >>
> >>> Such a requirement will be breaking. Breaking changes are out of scope.
> >> How is it a breaking change to limit what documents are allowed to be
> >> *generated*?
> >>
> > Because JSON is currently being used in applications that deliver those
> codepoints.
>
> Can you say why an application would do that, given the JSON specification?
>
> --Paul Hoffman
>
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