Re: [Boost-users] variant visitor using SFINAE problem

Subject: Re: [Boost-users] variant visitor using SFINAE problem
From: Olaf Peter (ope-devel_at_[hidden])
Date: 2013-05-26 12:52:13

Am 26.05.2013 15:20, schrieb Igor R:
>>> What visit() overload did you intend to call for vector<int>? Note
>>> that enable_if condition:
>>>           mpl::and_<
>>>               boost::has_range_const_iterator<VisitableT>,
>>>               boost::is_void<typename VisitorT::result_type>
>>>           >,
>>>
>>> seems to be fulfilled for vector<int> case, doesn't it? But it's
>>> obviously not the right overload, as int is not variant.
>>
>>
>> thank you, you did point out it; unfortunately, my extension doesn't
>> compile.
>
>
> Because you actually should apply is_variant metafunction to the
> value_type of the container, not to the container itself:
>              mpl::not_<is_variant<typename VisitableT::value_type> >,
> <....>
>              is_variant<typename VisitableT::value_type>,
>

Now, I've got it; thanks a lot Igor!