[Cython] Operators for ctypedef struct

[Stefan Behnel]

Dag Sverre Seljebotn wrote:
> Stefan Behnel wrote:
>> Dag Sverre Seljebotn wrote:
>>> Robert Bradshaw wrote:
>>>> I am also for supporting only a subset of what  
>>>> is possible--if one really needs crazy stuff like differently  
>>>> implemented prefix/postfix decrements and -> vs (*). one can code in C 
>>>> ++ or use clever macros. (Would we need to expose ++, a.k.a  
>>>> "__next__" for STL iterators?)
>>> Yes, you need ++/-- for std::list<T>::iterator, which doesn't accept any 
>>> form of +=
>> Am I missing something here? Why isn't the for-loop syntax enough for C++
>> iterators?
> 
> Who's saying that you always want to iterate through all elements from 
> beginning to end in one go?

Well, it's the most common case, at least. For the rest, there's reversed()
and islice(), which we could define (and optimise) on C++ iterators. Maybe
just our own version (as we might have to fix up the semantics), such as
"cython.cppitertools.islice()". Although overriding the standard function
might make life a lot easier for users.

I (basically) never used C++, so I may not be aware of all implications,
but I would prefer not reinventing stuff that Python already has, just
because we are dealing with a different 'backend'. The fewer things we need
to add to the language, the more seamlessly the C++ integration will become.


> But yes, one could use the for-loop syntax for that specific case.
> 
> (However myself I'm in favor of even getting the most basic things 
> working before adding support in higher-level constructs.)

But isn't the for-in-loop the most basic thing that you could get to work
for iterators? (at least from a Python POV...)

Stefan