Re: [boost] Help with iterator helpers

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2002-01-29 09:29:20

----- Original Message -----
From: <nbecker_at_[hidden]>

> I was hoping to find a simpler example.  One thing not clear to me is
> the first template parameter T.  It says "operand type".  In the
> example, it is set to "test_iter<T,R,P>", which is a self-reference.
> I'm confused.

The iterator helpers use the same idiom as the rest of the operators library
templates: the first parameter is the type to which you are adding the
operator functionality, i.e. the derived class. Don't worry; it's correct
and it works.

>     David> FWIW, most people find the iterator helpers aren't that useful
now that we
>     David> have the iterator adaptor library. It does a lot more to
automate the job of
>     David> making correct and useful iterators.
>
> I'll have a look.  I thought the adaptors were, well, adaptors.  In
> this case, I'm not adapting an existing iterator, but making a new
> one, so I didn't think that the adaptors were applicable.

You can adapt anything; it doesn't have to be an iterator. Your iterator has
some state data, right? Just adapt that.

-Dave