std.v2020.algorithm etc[ WAS: Is run.d going to be expand for runtime and the phobos library?]

[Jon Degenhardt]

On Monday, 22 June 2020 at 02:52:57 UTC, Andrei Alexandrescu 
wrote:
> On 6/21/20 10:47 AM, Andrei Alexandrescu wrote:
> One more thing before I forget - we should drop classes that 
> are ranges. They add too much complication. The functionality 
> would still be present by wrapping a polymorphic implementation 
> in a struct.

I have used class-based ranges quite a bit to implement ranges 
with reference semantics. Classes are very convenient for this 
because the implementation is structurally very similar to a 
struct based implementation. Typically, replace 'struct' with 
'final class' and modify a helper function constructing the range 
to use 'new'. It's amazingly easy.

So - What aspects of class-based ranges is it valuable to drop? 
Polymorphism/inheritance? Reference semantics? Both?

I haven't found a need for polymorphism in these ranges, just 
reference semantics. I realize that the Phobos experience is the 
opposite, that reference ranges are rarely used. Could be that my 
design choices could be modified to eliminate reference ranges. 
Could also be that approaches needed in general libraries are not 
always necessary in code targeting specific applications. Not 
trying to make hard claims about this. Just pointing out where 
I've found value.

--Jon