[Development] QList

[Giuseppe D'Angelo]

Il 27/03/2017 22:56, Thiago Macieira ha scritto:
> On segunda-feira, 27 de março de 2017 11:14:24 PDT Giuseppe D'Angelo wrote:
>> If we can't make it an alias, can we start adding extra functions for
>> the various QStringRef *ref() methods (in QXmlStreamReader,
>> QRegularExpressionMatch, probably elsewhere too), returning QStringView?
> 
> Never return QStringView in our API. It's as bad as returning a const 
> reference.
> 
> In fact, that's a good rule of thumb: if you could have used a const QString & 
> in that function, you can use QStringView. Otherwise, return QString by value.

Why should it bad if what you want return is precisely a "const
reference" over QString-like data? Isn't that the whole reason why we
have functions returning QStringRef right now (lacking a QStringView)?
(And also the reason why QStringView itself returns QStringViews?)

Example of use case: a tokenizer operating over QString-like data,
returning each token as a QStringView, with no memory allocations --
possibly even noexcept (narrow contract on the source string). Why would
I want to return QStrings for this use case and super-pessimize it?

Cheers,
-- 
Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (UK) Ltd., a KDAB Group company | Tel: UK +44-1625-809908
KDAB - Qt, C++ and OpenGL Experts

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