Re: [boost] [multi_index] Taking advantage of C++17 auto template params to simplify key specification

27 Sep 2017


      El 27/09/2017 a las 19:15, Steven Watanabe via Boost escribió:
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AMDG
On 09/27/2017 06:13 AM, Joaquin M López Muñoz via Boost wrote:
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El 27/09/2017 a las 13:47, Dominique Devienne via Boost escribió:
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On Wed, Sep 27, 2017 at 12:53 PM, Joaquin M López Muñoz via Boost <
boost@lists.boost.org> wrote:
<snip>
C++17 def#2
[...]
I'm out of my depth here, but the fact you use inheritance means the
two types are not the
same as a consequence, right? I.e. std::is_name
is false?
Correct, these are different types.
<snip>
No, template aliases don't support partial specialization. But I don't
see any fundamental
problem with subclassing.
To make them be the same type, the best way is
to reverse it so that member, const_mem_fun, etc.
are aliases for key.
Nice idea, but alas not applicable here since I want member etc. to 
remain C++03 compatible.
Another approach would be to write a template<auto Member> struct 
key_impl{using type=...;}
metafunction class here all the partial specialization goes and then do
template<auto Member> using key=typename key_impl<Member>::type. Either way,
the issue raised by Dominique does not cause any trouble AFAICS.

Joaquín M López Muñoz