How to make rsplit (like in Python) in D

[Uranuz via Digitalmars-d-learn]

On Saturday, 1 October 2016 at 16:45:11 UTC, Uranuz wrote:
> How to make rsplit (like in Python) in D without need for extra 
> allocation using standard library? And why there is no 
> algorithms (or parameter in existing algorithms) to process 
> range from the back. Is `back` and `popBack` somehow worse than 
> `front` and `popFront`.
>
> I've tried to write somethig that would work without 
> allocation, but failed.
> I have searching in forum. Found this thread:
> https://forum.dlang.org/post/bug-10309-3@http.d.puremagic.com%2Fissues%2F
>
> I tried to use `findSplitBefore` with `retro`, but it doesn't 
> compile:
>
> import std.stdio;
> import std.algorithm;
> import std.range;
> import std.string;
>
> void main()
> {
> 	string str = "Human.Engineer.Programmer.DProgrammer";
> 	
> 	writeln( findSplitBefore(retro(str), ".")[0].retro );
> }
>
> Compilation output:
> /d153/f534.d(10): Error: template std.range.retro cannot deduce 
> function from argument types !()(Result), candidates are:
> /opt/compilers/dmd2/include/std/range/package.d(198):        
> std.range.retro(Range)(Range r) if 
> (isBidirectionalRange!(Unqual!Range))
>
>
> Why I have to write such strange things to do enough 
> wide-spread operation. I using Python at the job and there is 
> very much cases when I use rsplit. So it's very strange to me 
> that D library has a lot of `advanced` algorithms that are not 
> very commonly used, but there is no rsplit.
>
> Maybe I missing something, so please give me some advice)

Sorry for noise. It was easy enough:

import std.stdio;
import std.algorithm;
import std.range;
import std.string;

void main()
{
	string str = "Human.Engineer.Programmer.DProgrammer";
	
	writeln( splitter(str, '.').back );
}


But I still interested why the above not compiles and how to do 
`rfind` or indexOf from the right in D. I think even if we do not 
have exactly algorithms with these names we could provide some 
examples how to *emulate* behaviour of standard functions from 
other popular languages)