[phobos] Ranges using runtime interfaces

[Shin Fujishiro]

David Simcha <dsimcha at gmail.com> wrote:
> Hmm.  It's worth considering, but I see at least two problems.
> 
> 1.  Do we have a practical use case for it?  I don't generally believe 
> in adding complexity without clear use cases for said complexity.

I'm not sure.  I/O-related ranges tend to have chunk-writing overloads:

  void put(E value);
  void put(E[] chunk);

And the Appender has a similar overload for bulk appending.  But such
ranges can work with only one of those overloads.


> 2.  The base interface is OutputRange!(E).  If I change the base 
> interface to OutputRange!(E...), then OutputRange!(uint, double) won't 
> be a subtype of OutputRange!(uint).  This is self-evidently ridiculous.  
> I could maybe make OutputRangeObject!(E...) inherit from 
> OutputRange!(E[0]), OutputRange!(E[1]), ..., OutputRange!(E[$ - 1]), but 
> other than nasty string mixins D doesn't provide a way to inherit from a 
> tuple of interfaces.

Oh, really?  That's bad.  I thought tuples could be used in the class
inheritance list.  IIRC something like the following also does not work
due to a deep inheritance bug:

interface OutputRange(E...) : OutputRange!(E[1 .. $]) {
    void put(E[0] e);
}

Then, maybe we should put off supporting this anyway...


> On 8/20/2010 9:26 PM, Shin Fujishiro wrote:
> > David Simcha<dsimcha at gmail.com>  wrote:
> >    
> >> In addition to the changes I made last night, I've also made the
> >> following changes:
> >>
> >> 1.  Change name to inputRangeObject/InputRangeObject.
> >> 2.  Add support for output ranges as outputRangeObject/OutputRangeObject.
> >> 3.  Remove the now ridiculous looking Hungarian notation on the interfaces.
> >>
> >> http://pastebin.com/U83YNJfJ is where it's at.
> >>
> >> Any more comments from anyone, or does this look ready to be checked in?
> >>      
> > Could you make OutputRangeObject able to accept multiple element types?
> >
> > template outputRangeObject(E...) {
> >      auto outputRangeObject(R)(R range) { ... }
> > }