Re: matching multiple template

From:
abir <abirbasak@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 9 Jul 2008 06:59:03 -0700 (PDT)
Message-ID:
<f3b427fc-9cf4-42da-ab96-a26609b88c21@d1g2000hsg.googlegroups.com>
On Jul 9, 6:37 am, "Eric Pruneau" <eric.prun...@cgocable.ca> wrote:

"abir" <abirba...@gmail.com> a =E9crit dans le message de news:
385bd2d8-d853-4e2d-bdad-35005952b...@p25g2000hsf.googlegroups.com...

i have atemplate
template<typename S> class Indexer{};
i want to have a specialization for std::vector bothconst&nonconst
version.
template<typename T,typename A> class Indexer<std::vector<T,A> > {}
matches only with nonconst version. anyway to match it for both? and
get if it isconstor nonconst?

Actually i want 2 specialization, one for std::vector<T,A>const&non
constother for std::deque<T,A>const&nonconst.

thanks
abir


I'm not sure if I understand what you really want to do but here is what =

I

think.

you have a class

template<typename S>
class Indexer{ };

and you want to specialize this class when S is a vector and when S is ac=

onstvector (samething with deque).

Here is how to do that. Note that I've removed the allocatortemplate
parameter to simplify the example but I amsure you will find a way to
integrate it!!!

template<typename T, typename CONT>
struct Indexer
{
     Indexer() { cout <<"1\n"; }

};

template<typename T>
struct Indexer<T, vector<T> >
{
     Indexer() { cout <<"2\n"; }

};

template<typename T>
struct Indexer<T,constvector<T> >
{
     Indexer() { cout <<"3\n"; }

};

template<typename T>
struct Indexer<T, deque<T> >
{
     Indexer() { cout <<"4\n"; }

};

template<typename T>
struct Indexer<T,constdeque<T> >
{
     Indexer() { cout <<"5\n"; }

};

int main()
{
     Indexer<int, vector<int> > a; // print 2
     Indexer<int, deque<int> > b; // print 4
     Indexer<int, vector<int>const> c; // print 3
     Indexer<int, deque<int>const> d; // print 5

     return 0;

}

------------------------

Eric Pruneau


Thanks for answering.
Actually this is what i have already. What i want is to match both
const & non const version in same specialization something like (this
is not a valid syntax of course),
 template<typename T>
 struct Indexer<T,const vector<T> | vector<T> >
 {
      Indexer() { cout <<"3\n"; }

 };
so i want both the match to succeed in same specialization. Also i
need to know which match is there.
i don't know if it is directly possible, but i am thinking having a
proxy class to delegate the responsibility.

thanks
abir

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