C++14

Submitted by axel on Thu, 01/11/2012 - 17:41

Hi,

Two weeks ago I participated at the ISO C++ standard meeting. It was my and CERN's first one and a pleasant surprise. A few news items:

  • The next two standards are planned for 2014 and 2017, with 2014 being a bit like 2003: mostly bug fixes and usability improvements.
  • There is now (thanks to CERN's presence :-) a working group on reflection in C++.
  • The next meeting will be in April, in Bristol. I will try to give a CERN computing seminar beforehand, such that we can collect your feedback on the proposals that will be discussed in Bristol.
  • There is a new web site on the future of the C++ standard: isocpp.org

Topics that were discussed in Portland were vectorization directives and parallel algorithms (sort etc). There were favorable votes on runtime-sized arrays void f(int n) { int arr[n]; ..., generic lambdas [](auto a){ return ++a;}, binary literals 0b10010001000001000 and digit separators to make for instance binary literals readable 0b1_0010_0010_0000_1000. There were very annoying problems with digit separators versus user defined literals (think the UDL _3d and hex numbers with digit separators), so the whole digit separator business is not yet resolved. For the others it's likely that they will at least end up in the 2017 standard.

Is there anything else you want to know? Ask, or watch Herb Sutter's live show tomorrow at 12:45 Pacific Time == 20:45 CERN time.

Cheers,
Axel

How about the back tick ` for

Submitted by Lode (not verified) on Wed, 12/12/2012 - 20:13.
How about the back tick ` for digit separators. That's an ASCII character that's not used by C++ yet as far as I know so that it doesn't conflict with anything.

Re: back tick

Submitted by axel on Wed, 19/12/2012 - 14:44.

Hi Lode,

Good idea! That was in fact one of the options discussed - including its major drawback that the back tick is not yet part of the C++ character set...

Cheers, Axel

D programming language does

Submitted by bioinfornatics (not verified) on Fri, 02/11/2012 - 18:55.
D programming language does already all these thing and it is much lesser complex than C++. Since i use D for me i cn't come back to C++ . If you compra D and C++ they are two case: - C++ and D is equivalent for given feature - D is better for given feature So they are no reason to continue with this language External ressource: - http://dlang.org/ - http://dlang.org/comparison.html - http://dpaste.dzfl.pl/ - D is a dragon, or why D matters for Bioinformatics http://blog.thebird.nl/?p=93

For me D is nice "toy"

Submitted by Devid (not verified) on Sun, 04/11/2012 - 19:31.
For me D is nice "toy" Language. It has a lot of great features that I wish would also be available in C++ too. The problem is that D is too small to be used. There is no gut IDE sot D like Visual Studio or XCode for C++. There is no solid highly optimized compilers for D. Like Clang or Intel C++ compilers. Yes I know there is D compiler in work based on LLVM but it is not mature enough. There are no tons of libraries for D and it is not possible to use C++ together with D. So for now there is no reason for me to use D even if it looks really gut. As opposite C++11 is now even better C++ and Clang has already solved a lot of problems with is. With Cling we even have REPL for C++11 !!!

Re: D

Submitted by axel on Sat, 03/11/2012 - 20:41.

Hi,

Thanks for your comment (that I edited to correct a link)! There are many nice languages out there, also compiled ones. Some people favor D, some Go, some something else. The main problem with all these languages: educating thousands of students to learn it risks being a waste of time, see Tiobe (or any other index). Part two of the problem: who's going to rewrite the 50 million lines of C++ code that we have and rely on, in production, for large scale data analysis, in a million whatever-your-currency publicly funded endeavor? Anyone?

Until we have our code re-written in D, or until there is a language that is able to interface through headers with C++ (and is not threatening our investment through vendor lock-in) we'll have to stick to C++. Maybe we're unique in this respect, but I doubt that. Yes, I find oneway streets and our inability or inertia to move (e.g. to C++11!) frustrating too, but it's reality that we have to cope with.

Cheers, Axel.

reflection !!!

Submitted by DevO (not verified) on Fri, 02/11/2012 - 17:10.
This is great new. We finally will get Reflection in C++ !!!

Re: reflection

Submitted by axel on Fri, 02/11/2012 - 17:18.

Hi DevO,

Thanks for your enthusiastic comment! Note though that we will now discuss reflection for C++; whether and when it comes and what it will look like will be part of the discussion... Still: I agree that this is a huge first step!

Cheers, Axel.

Hi Axel, What we really need

Submitted by Devid (not verified) on Sun, 04/11/2012 - 19:39.
Hi Axel, What we really need is C++ is Compiler Time "reflection" with minimal runtime overhead. Of course it would be great to have runtime "reflection" too but may be later... Customizable but not invasive. Should work with Libraries that you can not change. Something like "Rich Pointers" sound already interesting... Build into Compiler, no other tools are needed. Should be Optional, (on / off) compiler switch. I already started to use C++ reflection abed on Clang and this allow to do thing that appears to be impossible before. Sterilization in only small part of it. Cheers, Devid.

OpenC++?

Submitted by Kurt Stephens (not verified) on Sun, 02/12/2012 - 01:38.
OpenC++ maybe what you are looking for. Unfortunately, it hasn't been updated since 2004.

Re: OpenC++

Submitted by axel on Mon, 03/12/2012 - 12:08.

Hi Kurt,

Thanks for your comment! I don't think we need more tools - we have tools. What we need is a runtime source of reflection, or language features that facilitate binding to such a library.

Cheers, Axel.

Work at CERN, in C++/ROOT team

Submitted by Imax (not verified) on Fri, 02/11/2012 - 15:15.
Hi Axel, slightly out of topic, but could you please mention what are the possibilities to get a job at CERN, in C++/ROOT team? Especially for those who are not fortunate enough to live in a CERN member state country. Thanks!

Re: Work at CERN

Submitted by axel on Fri, 02/11/2012 - 17:15.

Hi Imax!

Thanks for your interest! All the official recruitment information is here: ert.cern.ch. But if your passport comes from a non-member state then that's a lot more difficult.

Depending on your age, being a summer student can be an amazing experience. Else you'd have to convince us for instance through your patches that you know so much about cling that we'd like to have you over for a few months, where CERN could contribute to your subsistence. And who knows, our group might again apply for a few Google Summer of Code projects in 2013.

If you apply for anything then please let us know (ideally before submitting the application) so we can pick you out of the long :-) list of applicants! Hope to see you soon at CERN!

Cheers, Axel