Angus Leeming <angus.leeming@btopenworld.com> writes:
David Abrahams wrote:
In the section "Template Arguments for iterator_facade" is the subsection "CategoryOrTraversal". I suspect that should be "CategoryOfTraversal" (s/Or/Of/).
The iterator_adapter docs spell it "CategoryOrTraversal" too.
No, the spelling is as intended.
It's either an iterator category tag (such as std::random_access_iterator_tag) or an iterator traversal tag (such as boost::random_access_traversal_tag).
Thanks for the explanation.
Would it not be worthwhile putting something like this in the documentation? Perhaps in iterator_facade.html#tutorial-example where the CategoryOrTraversal template parameter is explained and where the explanation mentions 'iterator tranversal concepts' only. Indeed clicking on the link of that name takes me to a point where the tables again mention only traversal.
Huh? CategoryOrTraversal Now we have to determine which iterator traversal concept our node_iterator is going to model. Singly-linked lists only have forward links, so our iterator can't can't be a bidirectional traversal iterator. Our iterator should be able to make multiple passes over the same linked list (unlike, say, an istream_iterator which consumes the stream it traverses), so it must be a forward traversal iterator. Therefore, we'll pass boost::forward_traversal_tag in this position [1]. [1] iterator_facade also supports old-style category tags, so we could have passed std::forward_iterator_tag here; either way, the resulting iterator's iterator_category will end up being std::forward_iterator_tag. What am I missing? -- Dave Abrahams Boost Consulting www.boost-consulting.com