DIP67: Associative Ranges

[Freddy via Digitalmars-d]

On Tuesday, 28 October 2014 at 22:44:32 UTC, Freddy wrote:
> http://wiki.dlang.org/DIP67
> Abstraction over the build-in associative array(one type of 
> range
> for containers and another type for dynamic generators).
> Plese criticize.

Does any one now a better way to implement lazy associative
ranges other than my KeyType and ValueType hack?