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Subject: Re: Concatenating unicode string literals
From: Alisdair Meredith (alisdairm_at_[hidden])
Date: 2020-07-13 08:33:57


A little historical context, in case you feel like adding it to the paper, and
I had already researched the paper trail!

Concatenating narrow and wide string literals was made defined behavior
for C++11 by Clark Nelson’s paper synchronizing with the C99 preprocessor:
    http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1653.htm
adopted at the Mont Tremblant 2005 meeting (paper trail on this one is
tricky!)

The conditionally supported implementation-defined behavior for concatenating
unicode and wide string literals was a feature of the original proposal for unicode
characer types:
   http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2249.html
adopted at the Oxford 2007 meeting.

The final rule to make u8 literals ill-formed when attempting to concatenate with
a wide string literal was in the original paper proposing u8 literals:
   http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2442.htm
adopted at the Kona 2007 meetings.

All these changes occurred in the development of C++11.

AlisdairM
   

> On Jul 10, 2020, at 19:42, Jens Maurer <Jens.Maurer_at_[hidden]> wrote:
>
> On 10/07/2020 08.00, Tom Honermann wrote:
>> On 7/9/20 5:07 PM, Jens Maurer wrote:
>
>>> https://wiki.edg.com/pub/Wg21summer2020/SG16/concatenation.html
>>>
>>> I think the overlap with P2029 is very manageable, so this can
>>> go ahead regardless.
>>
>> Excellent!
>>
>> Some minor suggestions for the paper:
>> - Make the compiler-explorer URL an actual link.
>> - Mention that the SDCC C compiler does actually support mixed
>> concatenations as reported on the WG14 mailing list
>> (http://open-std.org/jtc1/sc22/wg14/18105). I verified that SDCC
>> version 4 does accept such code (version 3.5 does not), though I didn't
>> verify the behavior.
>> - Explicitly state the four major C++ compilers (there could be more (or
>> less) in the future and the compiler-explorer link may go dark some day!).
>
> All fixed. Enjoy:
>
> https://wiki.edg.com/pub/Wg21summer2020/SG16/concatenation.html
>
> Jens


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