DMD 0.170 release

[Sean Kelly]

Walter Bright wrote:
> 
> So I've been interested in having D algorithms and collections not need 
> iterator types at all. I've been experimenting with doing STL's 
> algorithms in D, and it became clear that to make them complete, reverse 
> iteration was necessary. foreach handles forward iteration, and opIndex 
> handles random access. Various ways of doing reverse traversal without 
> core support always seemed to involve creating dummy classes and other 
> hackish stuff. Promoting it to a supported statement makes it pretty 
> clean for the user to understand and use.
> 
> Essentially, I think foreach_reverse is the missing piece to be able to 
> implement all of STL's algorithms code for D.

I think I agree, but for the sake of argument, how would D handle 'find' 
  operations on sequences that don't support opIndex?  At some point, a 
generalizable bookmark is almost necessary for a faithful implementation 
of some C++ algorithms.  Also, many of these algorithms also require 
iteration across two sequences simultaneously, which doesn't map very 
cleanly into foreach.  Consider a substring-style find operation 
(std::search), for example, where both the pattern and target types do 
not support opIndex or opSlice.  I might argue that it's a bit silly or 
unrealistic to desire such an operation, but the C++ algorithm library 
does support it.


Sean