Re: partial partial template specialization?

From:
Carl Barron <cbarron413@adelphia.net>
Newsgroups:
comp.lang.c++.moderated
Date:
Sat, 24 May 2008 00:55:37 CST
Message-ID:
<230520082322391016%cbarron413@adelphia.net>
In article
<6180b69d-db7d-429b-a6b8-9bd0c3d42db9@e53g2000hsa.googlegroups.com>,
<rbinion@comcast.net> wrote:

Unfortunately I can not seem to get this approach to work. As I
indicated in my previous reply, my compiler seems to have problems
making friends. The primary template for the helper class receives
friend status, but the specialization does not ...


    overload a function with a dummy arg call that function
with an appropriate dummy arg, in operator T(); such as:
    template <class T,int Min=0,int Max = 0>
    class Foo
    {
       template <class U>
       struct identity{typedef U type;};

       T do_conversion(identity<T>)
       { /* general conversion */}
       char do_conversion(identity<char>)
       { /* special conversion */}
    public:
       operator T() {return do_conversion(identity<T>());}
    //...
};

or use boost::enable_if/disable_if to choose function
that operator T() will call.

boost::enable_if /disable_if and is_same, are easy enough to write
if you don't want to use boost.

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