On Tue, 27 Oct 2026 at 22:50, Steve Downey <sdowney_at_[hidden]> wrote:

>
>
> On Tue, Oct 27, 2026, 16:20 Jan Schultke via SG16 <sg16_at_[hidden]>
> wrote:
>
>>
>>
>> On Tue, 27 Oct 2026 at 21:05, Tiago Freire <tmiguelf_at_[hidden]> wrote:
>>
>>> > I also brought up that I don't see why this API needs to be based on
>>> views. This seems much more intended for transcoding a file or network
>>> packet once, at the program boundaries, in order to obtain Unicode. Views
>>> are useful for e.g. temporarily iterating over the code points of a UTF-8
>>> string, without needing to allocate. > The API being view-based actually
>>> hurts its usability in my opinion.
>>>
>>>
>>>
>>> How so? What alternative API would you use?
>>>
>>
>> I would use an algorithm rather than a view. Range goes in, code units
>> come out.
>>
>> Part of the problem is that if you have views (and notably a distinct
>> type for each codec), you end up with:
>>
>> std::u32string decode(std::string_view text, std::codec c) {
>> switch (c) {
>> case codec::utf8: return decode_with<codec::utf8>(text);
>> // 199 more cases ...
>> }
>> }
>>
>> Where std::codec c is a runtime parameter obtained based on, say, the
>> contents of <meta charset=...> HTML elements.
>>
>
> constexpr std::optional<codec> get_encoding(std::string_view label)
> noexcept;
>
>
> https://github.com/steve-downey/transcode/blob/main/include%2Fbeman%2Ftranscode%2Flabel.hpp#L21
>
> It's the API your web browser uses to read that charset lable right now,
> as you are reading this.
>

Yes, but you can't use the result of that function to create a type, and
every specialization of decode_with<C> is a distinct type.

So to decode 'text' using the codec 'c' you need a switch over all
enumerators.



>
>
> The paper seems to have evolved a bit since I made my Mattermost comments
>> and now has some ways to work with runtime codecs. It was just views last
>> time I saw it, but that was an early draft.
>>
>> Still, I find the use case for views contrived. Why wouldn't you just
>> transcode a single time at program boundaries, in which case an algorithm
>> is better suited than a view?
>> --
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>> Link to this post: http://lists.isocpp.org/sg16/2026/10/4896.php
>>
>