Wanted: best way to express default expectations

[Paul Backus]

On Monday, 14 October 2019 at 13:00:14 UTC, Dukc wrote:
> 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.

Pretty sure you don't need the foreach loop in this example; you 
can just use `take`:

iota(10)
     .filter!(x => x%2)
     // ...
     .take(1)
     .each!writeln;