2D (or higher) equivalent of ranges?

[Tobias Pankrath]

> More exotic:
>
> http://svn.dsource.org/projects/dranges/trunk/dranges/docs/recursive.html

That looks like a compile time composite pattern and I'd say it's 
a natural way to iterate over every form of graph. To be a 
equivalent to ranges in the std.algorithm sense, they must also 
be a good vehicle to implement graph algorithms effectively. I'd 
question this for the recursive ranges. How would you implement 
Dijkstra with r-ranges?