Re: [apps-discuss] Fw: draft-pbryan-zyp-json-pointer: name syntax for non-ASCII

"Martin J. Dürst" <duerst@it.aoyama.ac.jp> Mon, 28 November 2011 11:23 UTC

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Date: Mon, 28 Nov 2011 20:22:53 +0900
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Subject: Re: [apps-discuss] Fw: draft-pbryan-zyp-json-pointer: name syntax for non-ASCII
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On 2011/11/25 2:15, t.petch wrote:
>   ---- Original Message -----
>   From: "Graham Klyne"<GK@ninebynine.org>

>> I spotted this discussion and was reminded that one of the older URI specs had
>> some explicit discussion of characters and octets and encoding.  I recall a
> line
>> that looked something like this:
>>
>>     URI characters ->  URI octets ->  URI octets %-encoded to US-ASCII
>>
>> but I can no longer find it (quickly).  But
> http://www.ietf.org/rfc/rfc3986.txt
>> sections 1.2 and section 2 (esp. intro) address some of the issues.  The point
>> being that character encoding to octets is a separate concern from %-encoding
> to
>> URI (or IRI) on-the-wire characters.
 >
>   My bible for this is RFC2130 which gives
>
>   character->coded character set->character encoding scheme->transfer encoding
>   syntax
>
>   which Unicode seemed to get spot on,

Of course, because Unicode is a character encoding.

> but HTML and URIs ... um

They are not character encodings, but work on a higher level. HTML 
pretty well conforms to http://www.w3.org/TR/charmod/#sec-RefProcModel, 
the Reference Processing Model of the Character Model for the World Wide 
Web. See also RFC 2070.

For URIs, the situation is indeed murky, because escaping (%-encoding) 
is on the octet level, rather than on the character level, and depending 
on the component, the character->octet mapping is undefined. But for new 
stuff, such as the syntax discussed in this thread, the character->octet 
mapping just has to be fixed to UTF-8, which brings that part of an URI 
mostly in line with the above model.

Regards,    Martin.