On Wednesday, June 27, 2012 22:29:01 Roman D. Boiko wrote: > On Wednesday, 27 June 2012 at 20:14:53 UTC, Steven Schveighoffer > > wrote: > > Removal of that element is perfectly possible, you just need to > > maintain a reference to its predecessor. Which SList's range > > does not keep track of. It all depends on tradeoffs of what > > you want for performance, vs. features. It's why I contend > > that generic singly linked list is difficult to create. Can't > > please everyone. > > Yes, I agree. > > > And iterators are not necessary, ranges are quite possible. > > In this respect it is not only a performance vs. features > tradeoff, semantics is (usually) different. Of course, we might > use a range for what is semantically an iterator. But it feels > unnatural for me. > > E.g., to point to an element in the middle of some range we would > need to create another range and pass it to a function along with > the original range. I would hesitate to call them ranges unless > that is explicitly a goal for some particular application. If > that was the case, it would require an explicit explanation. (IMO)
If you want a single element, then use take, takeExactly, or takeOne. For instance, that's what you do when you want to use remove in std.container (though apparently takeOne was missed as pointed out earlier in this thread, which needs to be remedied). It is true that dealing with ranges in this sort of situation is a bit more problematic than it is with iterators, but the take* functions take care of it as long as the container properly takes them into account (which std.container's containers are supposed to do). And if all you care about is having a range with one element and not whether the range is passable to a function on it's associated container, then the take* functions work just fine regardless of whether the container properly takes them into account. It's only an issue with the container, because the container needs its original range type rather than some arbitrary range which may have nothing to do with that container (the same happens with iterators - you just don't tend to wrap them in other types in the same way that happens with ranges). - Jonathan M Davis
