Re: [Json] Proposed minimal change for strings

[Paul Hoffman <[e-mail]>]

<hats on>

On Jul 2, 2013, at 6:26 PM, John Cowan <[e-mail]> wrote:

> Paul Hoffman scripsit:
> 
>> Proposal 1 (allow all code units in their unescaped form):
>> 
>>    A string is a sequence of zero or more Unicode code units [UNICODE].
> 
> I object to this, because "code unit" is not well defined without
> mentioning its size.  I suppose it is 16-bit code units that are meant,
> but if so, that must be said.  "If Parliament does not mean what it says,
> it must say so."

It does not appear that the Unicode Standard requires mentioning its size, at least in the definition of "code unit" in D77.

>> In section 2.2 (Strings):
>>  Leave the production for "unescaped" as-is.
>> In section 3 (Encoding):
>>  Add "Some strings, notably those that have unescaped surrogate code units
>>  (value 0xD800 to 0xDFFF), cannot be encoded in UTF-8."
> 
> While this statement is true, it is not the whole truth, which is that
> unescaped surrogate code units cannot be encoded in *any* encoding.

John is correct. After further review, we should have worded the above as "...cannot be encoded in any Unicode encoding form".

--Paul Hoffman