220 32263 <1b4adafd-e4b8-e5a8-4d58-035fc7cdaff0@technion.ac.il> article Path: news.gmane.org!.POSTED!not-for-mail From: Eyal Rozenberg Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Has it been proposed to allow "template <...>" to apply to multiple declarations/definitions? 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dkim=pass header.i=@technionmail.onmicrosoft.com; spf=neutral (google.com: 2a01:111:f400:fe1e::72c is neither permitted nor denied by best guess record for domain of eyalroz@alumni.technion.ac.il) smtp.mailfrom=eyalroz@alumni.technion.ac.il Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:32263 Archived-At: Well, two declarations/definitions, in the same namespace, in the same file, appears consecutively, and with the same template parameters are implicitly related already, I'd say. It's true that your proposal does not imply stronger relation and mine can be construed that way; but, well - so what? I mean, if someone wants to emphasize his consecutive pieces of code are unrelated, then s/he just won't put them in the same scope. As for your macro suggestion - come on... even ignoring the general aversion to macros, that's baroque-looking and confusing, declaring the template parameters far away from their use (both for your example and for mine). Having said that, though, I'll also say I don't think I want to try and forcefully "push" a suggestion which is met with resistance to the basic concept. I mean, maybe that's a worthwhile thing to do, but I don't have the 'psychological resources' to run a sort of a campaign of arguing with people. So, if you feel like combining suggestions - I think that would be great; if not that's also ok and I still support your proposal (for all the good that does you...) Eyal On 05/02/2017 04:21 PM, Matthew Woehlke wrote: > On 2017-04-29 12:49, Eyal Rozenberg wrote: >> Your proposal makes sense. I also think my proposal makes sense, and >> the justification is at least partially similar, i.e. "Why should a >> template specification apply to just a single >> definition/declaration?" as an example of DRY. >> [...] >> What do you think? (You = Matthew and everybody else) > > The concern I have with your proposal, that I think is shared by others, > is that your scope is a *pure* token repetition; that is, the template > parameters of the scope are each *independently* applied to the items > inside the scope. Compare with P0223 where - yes, even if the > *implementation* may work similarly - the entities in the scope are > logically related. > > Also, it just occurs to me, I think I can also solve your problem with > macros: > > #define MY_TEMPLATE \ > template > > MY_TEMPLATE bool all_of(InputIterator first, Predicate comp); > MY_TEMPLATE bool any_of(InputIterator first, Predicate comp); > > ...which lessens the motivation. While I *can* do the same thing for > classes, it's more awkward: > > #define MY_CLASS_TEMPLATE template > #define MY_CLASS_CLASS List:: > > MY_CLASS_TEMPLATE MY_CLASS_CLASS List(...) { ... } > MY_CLASS_TEMPLATE List& MY_CLASS_CLASS operator=(...) { ... } > MY_CLASS_TEMPLATE List::iterator MY_CLASS_CLASS find(...) { ... } > > Unlike the previous example, this is hardly an improvement over writing > out everything the long way. Also, P0223 offers an additional benefit > that doesn't apply to your case; namely, ability to use the class name > or types that are members of the class without extra qualifiers. > -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/1b4adafd-e4b8-e5a8-4d58-035fc7cdaff0%40technion.ac.il. .