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Subject: Re: WG14 N2688: Sterile characters
From: Corentin Jabot (corentinjabot_at_[hidden])
Date: 2021-04-06 15:49:10


On Tue, Apr 6, 2021 at 10:17 PM Jens Maurer via SG16 <sg16_at_[hidden]>
wrote:

> On 06/04/2021 05.33, Tom Honermann via SG16 wrote:
> > FYI, WG14 will be considering N2688 <
> http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2688.pdf>, a paper
> proposing to clarify how characters in character and string literals are
> handled when the execution character set (literal encoding) does not
> support representation for the source character (/basic-c-char/ or
> /universal-character-name/ in C++) or escape sequence (presumably just
> /simple-escape-sequence/ in C++, but the paper doesn't explicitly exclude
> numeric escape sequences).
>
> In C++, we say implementation-defined for character literals
> and, for string literals:
>
> If the string-literal’s encoding-prefix is absent or L, then
> the string-literal is conditionally-supported
> and an implementation-defined code unit sequence is encoded.
> Otherwise, the string-literal is ill-formed.
>
> So, C++ allows to pick a fresh random character every time
> the situation occurs, except that UTF-x string literals
> are ill-formed if they contain a non-encodable character
> (can those even exist?)
>
> Should SG16 offer a C++ perspective to WG14, e.g. via SG22?
>

We might want to postpone that discussion - Peter and I will bring an
updated revision of wg21.link/P1854 which makes that ill-formed in C++.
I will note that "non-encodable character" is certainly a better term than
"sterile character" (better yet: non representable abstract character)

>
> Jens
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