Re: C++0x: move() & a hypotheticyl language feature

From:
Alberto Ganesh Barbati <AlbertoBarbati@libero.it>
Newsgroups:
comp.lang.c++.moderated
Date:
Fri, 21 Nov 2008 13:52:36 CST
Message-ID:
<FCzVk.196870$FR.483761@twister1.libero.it>
Vidar Hasfjord ha scritto:

On Nov 10, 6:31 pm, SG <s.gesem...@gmail.com> wrote:

[...]
Disclaimer: I'm going to describe a *hypothetical* language feature
that solves these kinds of "dangling reference" problems. This is not
a proposal for C++0x.
[...]
   string&& operator+(string&& a : return, string const& b);


Interesting.

Here's an alternative syntax based on the new C++0x function
declaration syntax:

      [] operator + (string&& a, string const& b) -> a;


Very nice. Please notice that the "unified" function declaration syntax
(the one using []) was not voted into the CD. However, the idea is still
good, if you replace [] with auto:

  auto operator+(string&& a, string const& b) -> a;

Although probably less useful, we might also want to introduce a similar
syntax for member functions:

  struct A
  {
    auto operator=(const A&) -> this // returns A&
  };

the syntax should behave nicely with cv- and ref-qualifiers:

  struct A
  {
    auto f() -> this // returns A&

    auto g() & -> this // returns A&
    auto g() && -> this // returns A&&

    auto h() const -> this // returns const A&
  };

HTH,

Ganesh

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