Re: C++0x - nested initializer lists?

From:

Saeed Amrollahi <amrollahi.saeed@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 25 Jun 2011 07:01:50 -0700 (PDT)

Message-ID:

<a4de01e8-e86c-4b87-abc6-d5dcc029c9b9@j31g2000yqe.googlegroups.com>

On Jun 22, 8:15 pm, er <er.ci.2...@gmail.com> wrote:

Hi,

This does not compile under gcc-4.4: converting to 'std::tuple<>' from
initializer list would use explicit constructor. Is it conformant
anyway? Thanks.

    {
        typedef std::tuple<s_, int> t_;
        typedef std::vector<t_> v_;
        v_ v = {
            { "a", 1 },
            { "b", 2 },
            { "c", 3 },
            { "d", 4 },
            { "e", 5 }
        };
    }

I study the C++ standard document and asked your question
from C++ committee members.
You can't use initializer lists
with tuple because, tuple constructors are explicit, but the pair
constructors are not. You have to use the make_tuple function:

typedef std::vector<std::tuple<std::string, int>> v_;
v_ v = {
         std::make_tuple("a", 1),
         std::make_tuple("b", 2)
       };

HTH,
  -- Saeed Amrollahi