"Thorsten Ottosen" <nesotto@cs.auc.dk> writes:
"Anthony Williams" <anthony_w.geo@yahoo.com> wrote in message news:u0l8ddr1.fsf@yahoo.com... | "Thorsten Ottosen" <nesotto@cs.auc.dk> writes: | | > "Anthony Williams" <anthony_w.geo@yahoo.com> wrote in message | > news:k6m5enk7.fsf@yahoo.com... | > | "Thorsten Ottosen" <nesotto@cs.auc.dk> writes: | > | > | > | > in what way is it fragile?
| > my point was that this "fragility" is all over the place in C++. | | Yes, and we do what we can to avoid it. Introducing an instance into the core | of the language seems to be asking for trouble.
I would like to see examples of this "fragility".
I will construct one for you.
| > | If the "for(:)" construct calls free functions directly then you have no | > | control over which overload is selected, except by carefully choosing which | > | headers get included. If you need a header which changes the overload set in | > a | > | bad way, you're stuck. | > | > you make it sound like ADL is a horrible thing :-) | | It can be. Introducing ADL needs to be done carefully and with much | thought. begin and end are common words, and there may be overloads in scope | which are nothing to do with iterating. Actually, come to think of it, if I am | iterating over a range, I sometimes use *variables* called begin and end to | mark the ends of the range, which would completely scew up ADL:
the proposal demands
using std::begin;
So it does, I got carried away on my train of thought. My mistake. The example I gave were of ADL not applying, which it does if you add the using.
| > well, that's a problem already today. <std> is the way to go. | | In current cases where it happens, you can generally modify the call site to | ensure that the correct overload is called. If you can't access the call site, | because it is generated by the compiler, then you can't fix it. Note that the | problem is not that of required headers not being included, but rather that of | not-wanted headers being included.
I don't get it; can you show this?
I will construct an example.
| > | Also, the use of free functions implies that at least one header *has* to be | > | included, even to use the construct with arrays, which just feels wrong. | > | > we're trying to get rid of arrays, so it might even be a good idea. if it | > doesn't compiles. | | Who is "we"? There are many valid uses of arrays, not least of which for | fixed-content tables, which is precisely one scenario where I might wish to | use for(:) to iterate over the contents.
boost::array<T,N> should work there too.
Well, yes, but why use a library type when there's a built-in type that works just as well? Sounds like unnecessary additional overhead to me. Just because there's an alternative doesn't mean that my approach is not valid. Again, who's "we"? Anthony -- Anthony Williams Software Developer