[Dune] Comments on Dune Developer Meeting 2014.

[Robert Kloefkorn]

Hello Oliver,

> My argument for proposing the feature in the first place was ease of
> documentation. I wanted to be able to say "entity iterators are stl
> forward_iterators period". I don't actually need the postfix
> increment for anything.  But I am also not a strong believer in
> protecting the user from herself.  That's just not the C++ way.

According to the Forward Iterator documentation
(http://www.cplusplus.com/reference/iterator/ForwardIterator/) you would
also have to implement the operator->, which in our case does not make
sense, or it will be very slow and thus does not make sense. The reason
for that is, that a DUNE grid (in my opinion) is not a container. One
reason is, that the Entity is a proxy class and not a real object. From
that we deduct: If a DUNE grid is not a STL container why should it's
iterators behave like STL iterators?

To sum up. The usage of the range based for does neither require the
postfix increment not the operator->. So why have it then when it
requires more work for the implementer and even produces slow code. To
avoid 20 lines of documentation. Please, let's be reasonable.

Best,

Rob