Wanted: best way to express default expectations

[Dukc]

On Saturday, 12 October 2019 at 16:48:56 UTC, Jesse Phillips 
wrote:
>
> Sorry forgot the foreach break part.
>
> import std.stdio;
> void main()
> {
> import std.algorithm;
> import std.range;
>
> foreach(i; iota(10)
>     .filter!(x => x%2)
>     .until!(x => x>5)
>     .map!"a * a"
>     .filter!(x => x%4)) {
>     i.writeln;
>     break;
>    }
> }
>
> Note this is all done lazily so there is no walking of the iota 
> which happens.

This is not exactly what I wanted, but probably the best 
alternative overall. At least it's better than in C#, as you 
don't sacrifice as much performance for using functional 
pipelines.

But I still think an `if_not`, `ifnot` or some similar keyword 
would have it's place. Does anybody agree? Read: might it be 
worth a DIP?