On 21 May 2016 at 23:20, Andrei Alexandrescu via Digitalmars-d-announce <firstname.lastname@example.org> wrote: > On 05/21/2016 04:45 AM, Manu via Digitalmars-d-announce wrote: >> >> On 20 May 2016 at 18:26, Walter Bright via Digitalmars-d-announce >> <email@example.com> wrote: >>> >>> On 5/19/2016 11:50 PM, Manu via Digitalmars-d-announce wrote: >>>> >>>> >>>> Ah. Okay, well while this is a very interesting talk, I was indeed >>>> hoping you were going to make a D concepts proposal... do you have >>>> such a thing in mind, or are you against concepts in D? >>> >>> >>> >>> D has constraints. No point in adding concepts. >> >> >> I really struggle to agree. Constraints are a good first-step in that >> direction, but they're unwieldy, produce the worst looking function >> signatures (read: documentation) of literally any language ever >> conceived, relatively awkward error feedback, and very quickly get out >> of hand if you have many variations of possible constraints. > > > I guess a lot more detail would be necessary here. A bunch of good folks (at > least better than me) have worked for over a decade on C++ concepts and > three (three!) proposals later it's still unclear whether they're a good > idea. -- Andrei
I agree it's not clear to me either. I haven't seen any proposals for D. Have there been any? Constraints obviously work, but I do constantly find myself wishing there were something a little bit closer to the type system. I generally like where C++ is going. I think part of the problem with C++, as always, is that they are in a constant struggle to bolt things on to an ancient language with so many existing spiky angular edge cases that it always seems to become awkward. I think my biggest gripe with constraints in D though, is that they are quite pervasive when you start to produce generic API's, and the documentation becomes a massive problem. Every single person (seriously) I've ever introduced to D has struggled with the phobos docs as soon as constraints are presented. Many of us have raised this many times, and we've had a lot of discussion and various experiments with improving the documentation wrt existing constraints. I'm not sure we've doing a good documentation solution her, and I'm not even confident there's a good solution there. I just don't think it's a great way to express the problem. Concepts, or something like it, feels a lot more intuitive to me, and certainly lends much nicer to documentation and API presentation.