C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Template Parameter Forwarding          C++Talk.NET Forum Index -> C++ Language (Moderated) View previous topic :: View next topic   Author Message õá Guest Posted: Sun Apr 17, 2005 2:26 pm    Post subject: Template Parameter Forwarding There is a small proble I tried to solve. Imagine this template(it's just an example): template <typename T,typename T::type> struct Something; Now,everything is OK. But imagine I want to default the first parameter,e.g. to some metafunction. To be able to default it,it must be at the end of the template parameter list. To be able to use it in the second parameter type,it must be at the front. Nothing I tried seems to work,even traits. Is there anything I could do in this situation? Thanx. :-) [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Carl Barron Guest Posted: Sun Apr 17, 2005 9:20 pm    Post subject: Re: Template Parameter Forwarding õá <efim.slobodov233432 (AT) arcor (DOT) de> wrote: Quote: There is a small proble I tried to solve. Imagine this template(it's just an example): template <typename T,typename T::type struct Something; Now,everything is OK. But imagine I want to default the first parameter,e.g. to some metafunction. To be able to default it,it must be at the end of the template parameter list. To be able to use it in the second parameter type,it must be at the front. Nothing I tried seems to work,even traits. Is there anything I could do in this situation? Thanx. :-) Use inheritance like this: template struct*/}; template <class T,class T::type> struct something:something_base<T,T::type> { /* forwarding constructors */|; template <> struct something < default_type, default_type::type Quote: :something_base default_type::type { /* forwarding constructors */}; [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Ralph Zhang Guest Posted: Mon Apr 18, 2005 9:10 am    Post subject: Re: Template Parameter Forwarding why don't you just move that T::type into the class? like this: template<typename T> struct Something { typedef typename T::type type; }; [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top õá Guest Posted: Mon Apr 18, 2005 3:14 pm    Post subject: Re: Template Parameter Forwarding "> why don't you just move that T::type into the class? like this: Quote: template struct Something { typedef typename T::type type; }; Because I want that it is defaultable,but at the same time specifiable( ). Thanks for the answer,but just like I said,it wouldn't be nice if I had to specify the default template parameters. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ Language (Moderated) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.