C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Likely C++0x features Goto page 1, 2, 3, 4, 5  Next          C++Talk.NET Forum Index -> C++ language, library and standards View previous topic :: View next topic   Author Message Scott Meyers Guest Posted: Wed Jul 14, 2004 5:18 pm    Post subject: Likely C++0x features C++0x will offer new features compared to C++03+TC1+TR1. We don't know for sure what those features will be, but presumably some are much more likely than others. As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? I'm primarily interested in "big" features as opposed to "little" refinements to existing features. Forwading constructors qualify. Typeof/auto qualifies. Move constructors qualify. The const static definition thing doesn't qualify, but it's on my list, because, hey, it's my list, so I can break the rules if I want to :-) All help appreciated. Again, I know that we can't predict the future, but some things are a lot more likely than others. I'd just like to know what they are so that I can tell people who ask me. Thanks, Scott --- [ 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 Andrey Tarasevich Guest Posted: Wed Jul 14, 2004 7:35 pm    Post subject: Re: Likely C++0x features Scott Meyers wrote: Quote: FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? The last one - about const static integral members - is already in the standard. It was included in TC1, although it is formulated differently. TC1 changes the definition of what constitutes a "use" of an object. According to TC1 (3.2/2), appearance of an object in an integral constant expression (ICE) does not constitute a "use" of that object. Unused object require no definition. I.e. in TC1'ed version of the language there's no need to provide definitions for const static integral/enum members that appear only in ICEs (which is pretty much what is usually meant by "address is not taken", if I understood you correctly). -- Best regards, Andrey Tarasevich --- [ 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 Edward Diener Guest Posted: Thu Jul 15, 2004 1:58 am    Post subject: Re: Likely C++0x features Scott Meyers wrote: Quote: C++0x will offer new features compared to C++03+TC1+TR1. We don't know for sure what those features will be, but presumably some are much more likely than others. As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? I would be surprised, and disappointed, if a reflection mechanism doesn't make its way into the next C++ standard. This is especially so since, as I understand it, Mr. Stroustrup is working on this. Also a reflection mechanism is needed to allow effective C++ RAD programming environments without the extensions found in C++ Builder and Managed C++. I would hope the C++ committee would see the value of adding reflection to C++ to allow these possibilities as both C++ Builder and Managed C++ have proved strong environments for component based C++ programming and the ability to set properties and event handlers at design time. --- [ 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 David B. Held Guest Posted: Thu Jul 15, 2004 1:58 am    Post subject: Re: Likely C++0x features Scott Meyers wrote: Quote: [...] FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? [...] How about template aliases? (I hope!) Dave --- [ 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 Stephen Howe Guest Posted: Thu Jul 15, 2004 2:32 am    Post subject: Re: Likely C++0x features Quote: Should any of these not be on the list? What other things should be? I hope 1) Proper support for static asserts 2) Some formal langauge support for all the template tricks used to determine whether certain features are available or not. This would be useful to compiler vendors as it means they can issue some comprehensible error messages. Stephen Howe --- [ 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 David Abrahams Guest Posted: Thu Jul 15, 2004 6:54 am    Post subject: Re: Likely C++0x features Edward Diener wrote: Quote: I would be surprised, and disappointed, if a reflection mechanism doesn't make its way into the next C++ standard. This is especially so since, as I understand it, Mr. Stroustrup is working on this. Don't be; AFAIK Bjarne hasn't done anything with that project for quite a while and he's never brought a paper before the committee. The world at large has never even seen a prototype. Furthermore, Bjarne's work is not an in-language solution -- it relies on external tools to generate XML from GCC's debug info. Quote: Also a reflection mechanism is needed to allow effective C++ RAD programming environments without the extensions found in C++ Builder and Managed C++. I would hope the C++ committee would see the value of adding reflection to C++ to allow these possibilities as both C++ Builder and Managed C++ have proved strong environments for component based C++ programming and the ability to set properties and event handlers at design time. Many of us see the value, but I wouldn't assume what you're looking for is going to show up in the language standard unless someone like you, who really cares about it, leads the charge to put it there. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com --- [ 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 Joe Gottman Guest Posted: Thu Jul 15, 2004 4:13 pm    Post subject: Re: Likely C++0x features "Scott Meyers" <Usenet (AT) aristeia (DOT) com> wrote Quote: C++0x will offer new features compared to C++03+TC1+TR1. We don't know for sure what those features will be, but presumably some are much more likely than others. As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? Type-safe, portable enums. Joe Gottman --- [ 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 dietmar_kuehl@yahoo.com Guest Posted: Thu Jul 15, 2004 10:36 pm    Post subject: Re: Likely C++0x features Hi, "Edward Diener" wrote: Quote: I would be surprised, and disappointed, if a reflection mechanism doesn't make its way into the next C++ standard. Standardization works quite simple: somebody cares about something, he does the work involved in getting it standardized. That is, if you want reflection, work on this stuff! There is no need to be a member of the committee, although it admittedly would help to get a better feeling on how a proposal should look like and what is required. Also, somebody at in the committee will have to push the issue but I think there are several people who would be willing to bring something like this forward and discuss it in the process of creating a papber. However, apparently nobody is currently sufficiently interested to write a proposal on this issue. Quote: This is especially so since, as I understand it, Mr. Stroustrup is working on this. It is a while since I heard anything of XTI (eXtended Type Information). Also, I'm not sure whether it was intended to do what I would like it to do. In any case, if you want reflection (or whatever it will be called) in the next standard, you should not rely on others doing the work. -- <mailto:dietmar_kuehl (AT) yahoo (DOT) com> <http://www.dietmar-kuehl.de/> <http://www.contendix.com> - Software Development & Consulting --- [ 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 tom_usenet Guest Posted: Thu Jul 15, 2004 10:36 pm    Post subject: Re: Likely C++0x features On Wed, 14 Jul 2004 17:18:53 +0000 (UTC), [email]Usenet (AT) aristeia (DOT) com[/email] (Scott Meyers) wrote: Quote: C++0x will offer new features compared to C++03+TC1+TR1. We don't know for sure what those features will be, but presumably some are much more likely than others. As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. FWIW, this is my list, bearing in mind that I'm treating TR1 as already included, even though I know that it's not: - forwarding constructors - something like typeof (maybe auto, maybe both) - move constructors - no need to define const static integral members whose address is not taken Should any of these not be on the list? What other things should be? I'm primarily interested in "big" features as opposed to "little" refinements to existing features. Forwading constructors qualify. Typeof/auto qualifies. Move constructors qualify. The const static definition thing doesn't qualify, but it's on my list, because, hey, it's my list, so I can break the rules if I want to This gives a list of all the proposals: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1598.html Personally, in addition to your list I'd like to see variadic templates, better compile-time reflection, overloading operator. and improved string classes (const_string, string and rope - include a way of detecting a string literal at compile time to avoid copying it). A separate standard on C++ threading, including a memory model and a library including atomic primitives (hopefully) would be nice, but this possibly comes under POSIX's remit, not C++'s. Tom --- [ 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 dietmar_kuehl@yahoo.com Guest Posted: Fri Jul 16, 2004 1:00 am    Post subject: Re: Likely C++0x features Hi, Scott Meyers wrote: Quote: As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. The best guess is to look at what is currently more or less actively discussed. This information is publically available at <http://www.open-std.org/jtc1/sc22/wg21/>. Essentially you want to look at the list of papers, especially those in the Evolution section. When inspected more closely this should even give you a good impression on how things are intended to be done. ... and you can even participate by pointing out problems, possible resolutions to problems, create own proposals, etc. -- <mailto:dietmar_kuehl (AT) yahoo (DOT) com> <http://www.dietmar-kuehl.de/> <http://www.contendix.com> - Software Development & Consulting --- [ 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 dietmar_kuehl@yahoo.com Guest Posted: Fri Jul 16, 2004 1:01 am    Post subject: Re: Likely C++0x features Hi, David Abrahams wrote: Quote: Furthermore, Bjarne's work is not an in-language solution -- it relies on external tools to generate XML from GCC's debug info. Although I consider it questionable to use GCC's debug info for this, the general approach is valid: for reflection a la Java you would need an interface to access the information which is essentially some form of library plus the implementation thereof. The implementation can be generated from suitable compiler output and bound to the executable with the effect that programs not using the reflection mechanism are not affected at all. This form of reflection is, of course, useless for template programming. However, I would expect different approaches for RAD and template programming anyway... Since proposals are supposed to be backed up with an implementation before they are accepted into the standard (but an implementation is not a requirement for a proposal itself), it may be reasonable to create an implementation based on gccxml (see <http://www.gccxml.org>): this seems to provide the necessary information for some form of reflection. -- <mailto:dietmar_kuehl (AT) yahoo (DOT) com> <http://www.dietmar-kuehl.de/> <http://www.contendix.com> - Software Development & Consulting --- [ 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 Gabriel Dos Reis Guest Posted: Fri Jul 16, 2004 1:02 am    Post subject: Re: Likely C++0x features [email]dave (AT) boost-consulting (DOT) com[/email] (David Abrahams) writes: Quote: Edward Diener wrote: I would be surprised, and disappointed, if a reflection mechanism doesn't make its way into the next C++ standard. This is especially so since, as I understand it, Mr. Stroustrup is working on this. Don't be; AFAIK Bjarne hasn't done anything with that project for quite a while That is untrue -- that is a subject of active, daily, discussions between him, me and his students. :-) Quote: and he's never brought a paper before the committee. Agreed. Quote: The world at large has never even seen a prototype. Furthermore, Bjarne's work is not an in-language solution -- it relies on external tools to generate XML from GCC's debug info. We're working -- on daily basis -- on that project and things are evolving -- maybe not as fast as you'd like, but progress has been made. You're quite right that it is not a language built-in solution. As of today, it is a library solution and it can represent all existing C++ notions (classes, functions, templates, ...). However, we're not -- momentarily I hope -- using tools that rely on GCC. GCC's debug ouput is currently far too incomplete and unsuitable for getting some specific information (XTI as presented at the ACCU Spring Conference 2002 was mainly concerned with types, IPR represents whole translation/instantiation units). But it gets you somewhere. We're, at the moment, using competing compiler to generate the information we need. But IPR itself is a compiler-neutral component (and it ought to be). It is my hope that at some point GCC/g++ would accept competition. Students are currently, succesfully, using competing compiler. I see no technical, fundamental reasons why one could not do the same with GCC, and it is the project aim to be compiler neutral. Recent discussions on GCC mailing list makes me confident that the situation is changing on that front, and the fierce resistance I met a couple of months ago would no longer be an issue. -- Gabriel Dos Reis [email]gdr (AT) cs (DOT) tamu.edu[/email] Texas A&M University -- Computer Science Department 301, Bright Building -- College Station, TX 77843-3112 --- [ 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 David Abrahams Guest Posted: Fri Jul 16, 2004 3:15 am    Post subject: Re: Likely C++0x features [email]gdr (AT) cs (DOT) tamu.edu[/email] (Gabriel Dos Reis) writes: Quote: dave (AT) boost-consulting (DOT) com (David Abrahams) writes: | Edward Diener wrote: | | > I would be surprised, and disappointed, if a reflection mechanism doesn't | > make its way into the next C++ standard. This is especially so since, as I | > understand it, Mr. Stroustrup is working on this. | | Don't be; AFAIK Bjarne hasn't done anything with that project for | quite a while That is untrue -- that is a subject of active, daily, discussions between him, me and his students. :-) | and he's never brought a paper before the committee. Agreed. | The world at large has never even seen a prototype. Furthermore, | Bjarne's work is not an in-language solution -- it relies on external | tools to generate XML from GCC's debug info. We're working -- on daily basis -- on that project and things are evolving -- maybe not as fast as you'd like, but progress has been made. You're quite right that it is not a language built-in solution. As of today, it is a library solution and it can represent all existing C++ notions (classes, functions, templates, ...). Just to clarify -- I wasn't trying to make any judgements about XTI other than that it's got very little going for it in the "liklihood of standardization" department other than that it's Bjarne's project. At this point there's little reason to be surprised if it isn't part of the next standard... especially if it uses a tool external to the regular compiler. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com --- [ 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 David Abrahams Guest Posted: Fri Jul 16, 2004 4:55 am    Post subject: Re: Likely C++0x features [email]dietmar_kuehl (AT) yahoo (DOT) com[/email] ("dietmar_kuehl (AT) yahoo (DOT) com") writes: Quote: Hi, Scott Meyers wrote: As a non-member of the standardization committee who follows the process only informally but who is responsible for trying to help practicing programmers keep an eye on what is likely to happen in the future, I'd be interested in others' guesses as to what language and library features are likely to make it into C++0x. The best guess is to look at what is currently more or less actively discussed. This information is publically available at http://www.open-std.org/jtc1/sc22/wg21/>. Essentially you want to look at the list of papers, especially those in the Evolution section. I agree with Dietmar. With all due respect to those non-committee members who have posted, most of their posts seem a lot more like personal wishlists than accurate answers to the question you asked. If it's not in recent or active papers, it's not particularly likely to go in the next standard. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com --- [ 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 Gabriel Dos Reis Guest Posted: Fri Jul 16, 2004 5:08 pm    Post subject: Re: Likely C++0x features [email]dietmar_kuehl (AT) yahoo (DOT) com[/email] ("dietmar_kuehl (AT) yahoo (DOT) com") writes: Quote: Hi, David Abrahams wrote: Furthermore, Bjarne's work is not an in-language solution -- it relies on external tools to generate XML from GCC's debug info. Although I consider it questionable to use GCC's debug info for this, Well, Bjarne and I, independently, have come to conclusions that GCC's debu info is insufficient -- although it could be improved (I know how I can do that). Of course, Bjarne had been there before, and I guess I should be listening ;-) One fundamental problem with GCC's debug info is that it is incomplete on some specific point, but that can be improved. Another is lack of documentation and it is kind of frustrating to base work on something that could suddenly change and varies from release to release. But, as I said, it is not an unsolvable problem. Quote: the general approach is valid: for reflection a la Java you would need an interface to access the information which is essentially some form of library plus the implementation thereof. The implementation can be generated from suitable compiler output and bound to the executable with The aim of XTI was not just reflection -- reflection just happened to be *an* area of application. Once you have a data structure that can represent a translation unit, you can do much more than just reflection. -- Gabriel Dos Reis [email]gdr (AT) cs (DOT) tamu.edu[/email] Texas A&M University -- Computer Science Department 301, Bright Building -- College Station, TX 77843-3112 --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. 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