[Development] HEADS-UP: QStringLiteral

[Mutz, Marc]

On 2019-08-22 21:09, Danila Malyutin wrote:
> Can't it be alleviated/improved by providing user-defined literal for
> QString(Literal)? So that one would only write   a["b"_qs] = "c"_qs.

Yes.

   ++ways_to_construct<QString>;

:)

Fun aside, in C++20, this may actually alleviate some of the problems of 
QStringLiteral: if we use UDLs instead of lambdas, at least we make 
QStringLiteral data sharable with each other, because instead of a 
lambda function (which has a different, new type each time you type it), 
you'd instantiate a function template:

    "foo"_qs -> operator ""_qs<"foo">();

And the linker would sort out duplicates.

But up to and incl. C++17, the only way to make "foo"_qs work is by 
operator ""_qs(const char *, std::size_t), which is not a template, so 
all it can do is call QString::fromUtf8(), which would be a step back 
from what we have right now (since 5.7 or so, we guarantee that 
QStringLiteral doesn't allocate).

@Ville: please correct me if I'm wrong in the above. And: what's the 
reason I can't use the template <char...> version for string-literal 
UDLs?

Thanks,
Marc