Re: [Boost-users] [multi-index] multi-index type trait

Subject: Re: [Boost-users] [multi-index] multi-index type trait
From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2015-08-18 04:49:54

Elizabeta <elizabeta.petreska <at> gmail.com> writes:

> 
> Hi 
> how to test if the first index of boost::multi-index is key based or
> sequence based at compile time[...]

This can do:

    #include <boost/multi_index/ordered_index_fwd.hpp>
    #include <boost/multi_index/hashed_index_fwd.hpp>
    #include <boost/mpl/bool.hpp>
    #include <boost/mpl/front.hpp>
    
    template<typename Index>
    struct is_key_based_index:boost::mpl::false_{};
    
    template<typename... Args>
    struct is_key_based_index<
      boost::multi_index::ordered_unique<Args...>
    >:boost::mpl::true_{};
    
    template<typename... Args>
    struct is_key_based_index<
      boost::multi_index::ordered_non_unique<Args...>
    >:boost::mpl::true_{};
    
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