Re: Fixed String review

From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2019-12-02 09:07:35

wt., 26 lis 2019 o 18:34 Vinnie Falco via Boost <boost_at_[hidden]>
napisał(a):

> On Tue, Nov 26, 2019 at 8:31 AM Phil Endecott via Boost
> <boost_at_[hidden]> wrote:
>
> > You've chosen to return a string_view from substr().  I think that's
> > a bit dangerous; code that does "auto a = s.substr(...)" could end
> > up with a dangling view when s is a fixed string; this makes it
> > more difficult than it should be to migrate from one string type
> > to another, or to write generic code.
>
> Again we have to refer to the purpose of the container. People are
> using this for performance, the very last thing they want from
> substr() is to receive a copy. Users can opt-in to making a copy if
> they want, by constructing a new static_string from the string view
> returned by substr. If we go with your suggestion, no one can opt out
> of copies.
>

Even if this is a valid design choice when considered in separation, it is
clearly in conflict with the goal of being a drop-in replacement for
std::string. It looks like the library is aiming at being a drop-in
replacement for some subset of usages of std::string. It would be
beneficial to outline this subset clearly in the initial sections of the
documentation.

Regards,
&rzej;