C++ Logo

SG16

Advanced search

Subject: Re: [isocpp-core] Updated draft revision: D2029R2 (Proposed resolution for core issues 411, 1656, and 2333; numeric and universal character escapes in character and string literals)
From: Tom Honermann (tom_at_[hidden])
Date: 2020-07-08 12:54:17


On 7/8/20 6:43 AM, Alisdair Meredith wrote:
> Minor nit: I dislike normatively stating that a null character is
> appended after string concatenation in two places. I do like
> the addition of this directly to the phase 6 wording, so suggest
> that the original in [lex.string]p12 with its extra flowery language
> be demoted to a note.
That seems reasonable to me, I'll do so.
>
> In the normative text, AFAICT, in C++20 wide multi character
> literals must be supported, with an implementation-defined value,
> but after this paper they will be conditionally supported. I don’t
> see that design change addressed in the front matter. Same
> applies to non-encodable wide characters .

That is addressed in the "Proposed resolution overview" section. I can
add a statement about this to the introduction if you like.

I've been under the impression that the lack of conditionally-supported
for these is an oversight.  My understanding (and someone please correct
me if I'm mistaken; I don't recall where I was informed of this) is
that, in the C standard, implementation-defined includes an allowance
for rejecting the code as ill-formed, but in the C++ standard,
implementation-defined implies well-formed; hence the addition of
conditionally-supported.  If that understanding is correct, then the
updated wording corrects alignment with the intent of the C standard.

>
> (I thought this also applied to ordinary multi character literals,
> but it turns out they are already conditionally supported.)

Yup, in [lex.ccon]p1 <http://eel.is/c++draft/lex.ccon#1.sentence-4>.

Tom.

>
> AlisdairM
>
>> On Jul 7, 2020, at 16:33, Tom Honermann via Core <core_at_[hidden]> wrote:
>>
>> An update of D2029R2 (Proposed resolution for core issues 411, 1656, and 2333; numeric and universal character escapes in character and string literals) is now available at https://rawgit.com/sg16-unicode/sg16/master/papers/d2029r2.html. This addresses the feedback provided on the core mailing list in the thread starting at https://lists.isocpp.org/core/2020/06/9455.php.
>>
>> Wording review feedback prior to the next Core issues processing teleconference would be much appreciated!
>>
>> Tom.
>>
>> _______________________________________________
>> Core mailing list
>> Core_at_[hidden]
>> Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/core
>> Link to this post: http://lists.isocpp.org/core/2020/07/9545.php



SG16 list run by sg16-owner@lists.isocpp.org