From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2005-05-17 04:28:50
"Eric Niebler" <eric_at_[hidden]> wrote in message
| Thorsten Ottosen wrote:
| > "Eric Niebler" <eric_at_[hidden]> wrote in message
| > | vector<bool> creates all kinds of problems because generic code can't
| > | make assumptions about the behavior of vector<T>. vector<bool> is widely
| > | regarded as a Bad Move. Dave is saying that treating char different
| > | than, say, int is inviting the same sorts of problems. It will make it
| > | difficult to deal with T in generic code.
| > |
| > | I agree with Dave.
| > are these "problems" as serious as vector<bool> ?
| Yes. It's exactly the same situation. You are giving collection<X>
| different semantics than collection<Y>.
I guess my objection is to the use "exactly".
If I have
template< class T >
then I might need some traits for dealing with the bool case.
If I have
template< class Range, class OutIter >
void copy( const Range&, OutIter );
then I just need to be able to say what a Range means.
I think it would be wrong for the algorithm to assume anything; that would
not give the caller a chance to decide.
And that is why Pavol said, let's allow
copy( as_array( rng ), out );
copy( as_string( rng ), out );
copy( rng, out );
If we don't wan't to give string literals a special meaning in the range
we up with the rather clumsy
sub_range<string> r = find( rng, as_string( "foo" ) );
sub_range<string> r = find( rng, "foo" );
It is not obvious why you ever want to include the 0 in a literal, but if you
there should be a way to do so. Currently the isn't any support in the range
but there should be.
| BTW, I find your use of quotes rather "disparaging". If you think this
| situation is different, please give /technical/ reasons. Thanks.
Yeah, sorry. I guess I was equally annoyed by the claim that we had a new
simply by stating vector<bool> was a problem. I don't see that close an
and so the argument made by Dave could be used to to argue for anything.
I don't think the decisions of the range library was a big issue during the
Peter Dimov was, I think, one who said something along your opinion.
Anyway, it wasn't (and isn't) obvious to me that having special cases in the
range library is a bad idea---
as long as you can still explicitly ask for the other generic version.
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