Proto for Boost mailing list page: Re: [proto] Using a derived class as terminals in Boost.proto

Subject: Re: [proto] Using a derived class as terminals in Boost.proto
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2016-04-14 10:10:56

On 14 April 2016 at 14:43, Frank Winter <fwinter_at_[hidden]> wrote:

> Hi all!
>
> Suppose you'd want to implement a simple EDSL (Embedded Domain Specific
> Language) with Boost.proto with the following requirements:
>
>     Custom class 'Vector' as terminal
>     Classes derived from 'Vector' are working terminals too, e.g. Vector10
>
> [...]

template<typename T>
> struct IsVector
>   : mpl::false_
> {};
>
>
> template<>
> struct IsVector< Vector >
>   : mpl::true_
> {};
>
>
Surely this should be true for all types derived from Vector.

template<typename T, typename Enable = void>
struct IsVector
  : mpl::false_
{};

template<typename T>
struct IsVector<T, typanem enable_if< is_base_of<Vector, T> >::type>
  : mpl::true_
{};