C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  How come enum has class-wide scope ?          C++Talk.NET Forum Index -> C++ language, library and standards View previous topic :: View next topic   Author Message Meang Akira Tanaka Guest Posted: Thu Jan 06, 2005 3:31 am    Post subject: How come enum has class-wide scope ? Hope this will get more attention than my previous mail about this issue. I have been wondering how come it has been decided that values in an enum have to unique within a class or struct rather than only within the enum? Like shown in the followin example class { enum type1 { ok }; enum type2 { ok }; }; Any explanation would be appreciated thanks in advance Meang --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Victor Bazarov Guest Posted: Thu Jan 06, 2005 6:06 am    Post subject: Re: How come enum has class-wide scope ? "Meang Akira Tanaka" <meang (AT) post (DOT) com> wrote... Quote: [..] I have been wondering how come it has been decided that values in an enum have to unique within a class or struct rather than only within the enum? It's called "backward compatibility" IIRC. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Meang Akira Tanaka Guest Posted: Sat Jan 08, 2005 9:44 pm    Post subject: Re: How come enum has class-wide scope ? ===================================== MODERATOR'S COMMENT: Please don't overquote. Please don't top-post. ===================================== END OF MODERATOR'S COMMENT But haven't it been discussed whether a) the semantic of enum should be changed so that enum values should only be unique within the enum or b) proposed a new keyword which maybe could do the same as enum except that values only have to be unique within replace the enum. Of course there is a workaround by wrapping each enum in their own class, but does that make sense ? On Thu, 6 Jan 2005 06:06:29 GMT, [email]v.Abazarov (AT) comAcast (DOT) net[/email] ("Victor Bazarov") wrote: Quote: "Meang Akira Tanaka" <meang (AT) post (DOT) com> wrote... [..] I have been wondering how come it has been decided that values in an enum have to unique within a class or struct rather than only within the enum? It's called "backward compatibility" IIRC. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Victor Bazarov Guest Posted: Sun Jan 09, 2005 1:47 am    Post subject: Re: How come enum has class-wide scope ? "Meang Akira Tanaka" <meang (AT) post (DOT) com> wrote... Quote: But haven't it been discussed whether a) the semantic of enum should be changed so that enum values should only be unique within the enum I don't remember such discussion. If it existed, Google probably has a record of it. In any case, I personally do not agree with that. I suspect that I am not alone. Quote: or b) proposed a new keyword which maybe could do the same as enum except that values only have to be unique within replace the enum. New keywords are _really_ hard to introduce without breaking existing code. Quote: Of course there is a workaround by wrapping each enum in their own class, but does that make sense ? Since there are work-arounds certain problems, it is very unlikely the language is going to change to accommodate a whim or two. Quote: [..] Victor --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Dave Harris Guest Posted: Sun Jan 09, 2005 6:51 pm    Post subject: Re: How come enum has class-wide scope ? [email]meang (AT) post (DOT) com[/email] (Meang Akira Tanaka) wrote (abridged): Quote: But haven't it been discussed whether a) the semantic of enum should be changed so that enum values should only be unique within the enum Many times. Either here or in comp.lang.c++. The semantics would be similar to putting the enum in its own namespace, then adding a using declaration for that namespace to get the names out again. I don't recall seeing an argument against this, but it's not a high priority for most people either. -- Dave Harris, Nottingham, UK --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. 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