Paolo Bonzini <pbonz...@redhat.com> writes: > On 12/10/2015 12:00, Daniel P. Berrange wrote: >> I don't think your example here is a reasonable comparison when you consider >> the full extent of this patch series. You are only having to iterate over a >> single data structure here. At the end of this patch series we have to >> iterate over multiple data structures spread across the object instance >> and class hierarchy, so writing a 'next' like method is not as trivial >> as you suggest with this comparison. >> >> > Higher-order functions are a wonderful tool if the language is equipped >> > for them. In Lisp, for instance, you'd have everything in one place and >> > no need for the awkward marshalling and unmarshalling of arguments, >> > thanks to nested functions. >> > >> > In C, stick to loops. That's what the language supports. >> >> You're really arguing against use of function callbacks in general with >> this comparison to LISP. I don't think that's really practical in the >> real world, as any integration with event loop needs callbacks, which >> share al the same limitations as callbacks used with this foreach() >> style iterator. Given this I don't think banning use of callbacks in >> one specific scenario is really beneficial in general - its really >> just a personal style choice.
You're right, I do think callbacks in C are relatively awkward. But then you're attacking a strawman --- I did not advocate *banning* callbacks. That would be silly indeed. I did advocate for using them *sparingly*. There are cases where callbacks are simply required, and you quoted one. There are cases where callbacks compete with other techniques, and I quoted one. > I agree with Eric that in general loops are better than callbacks. Me. Eric's innocent :) > However, there are cases where iterators are just as awkward to write. > Considering that we have very few iterations on properties, I think your > patches are fine. Mind, I didn't actually object to them. I merely voiced my reasoned opinion on idiomatic iteration in C: stick to loops. Just to deter strawmen: that's a rule of thumb, not a law :)
