Re: [apps-discuss] Feedback on draft-ietf-appsawg-json-pointer-00

This thread has convinced me that it’s still easy after all these
years for people to go down rabbit holes on this issue, and therefore
the draft should be explicitly clear that key equality MUST be
determined codepoint-by-codepoint as Martin suggests.

 -T

On Thu, Mar 1, 2012 at 7:57 PM, "Martin J. Dürst"
<duerst@it.aoyama.ac.jp> wrote:
> On 2012/03/02 6:45, Paul C. Bryan wrote:
>>
>> On Thu, 2012-03-01 at 12:14 -0800, Mike Acar wrote:
>
>
>>> That is, if the reference token equals the name of some value within the
>>> object, move to that value. However, the tokens and values are Unicode
>>> strings; I'm not an expert in Unicode, but my impression is that testing
>>> Unicode strings for equality is not as simple as comparing sequences of
>>> bytes. For example, there are linguistic considerations: I believe
>>> German ö and oe are considered identical.
>>
>>
>>
>> While we may consider ö and oe to be linguistically equivalent, I do no
>> believe they are considered lexicographically equivalent in a Unicode
>> string comparison. Someone please correct me if I'm wrong. Would it help
>> to define the comparison as being lexicographical?
>
>
> No. Lexicographical is usually used with respect to order, not equivalence
> (see e.g. http://en.wikipedia.org/wiki/Lexicographical_order)
>
>
>>> There's also the question of JSON documents with different encodings;
>>> UTF8 is the default, but UTF-16 and -32 with both endiannesses are also
>>> supported. Presumably this question will disappear in practice, since
>>> implementations will operate on deserialized data structures, not on
>>> JSON texts.
>>
>>
>> Since they're logically the same underlying Unicode representations, I'm
>> not sure there's any issue to consider here.
>
>
> The best way to spec this is to say that equivalence is checked
> codepoint-by-codepoint. That solves both issues, because codepoints are
> independent of UTF-8/UTF-16/UTF-32, simply the Unicode character numbers.
>
> Regards,    Martin.
>
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