Re: [Boost-users] Question about enable_if / disable_if

Subject: Re: [Boost-users] Question about enable_if / disable_if
From: Roman Perepelitsa (roman.perepelitsa_at_[hidden])
Date: 2009-05-23 06:30:36

2009/5/23 Zachary Turner <divisortheory_at_[hidden]>

> Suppose I have a template function
>
> template<typename T> void f(const std::string&, T);
>
> which I want there to be a couple of different variants of.
>
> Version 1 - Enabled if and only if boost::is_same<T, bool>
> Version 2 - Enabled if and only if boost::is_same<T, foo>  (foo is a class)
> Version 3 - Enabled if and only if boost::is_enum<T>
> Version 4 - Otherwise
>
> Is there an easy way to express this?  It seems I run into a bunch of
> overload ambiguity problems.  I'm sure I can get around this by adding to
> every version the negation of all the other conditions, but this seems
> unnecessarily complicated.
>

1, 2 and 3 are disjoint, so you can use them as is. For 4 use negation of 1,
2 and 3.

Roman Perepelitsa.