.array required if FilterResult is fed to parallel [lazy]

[monkyyy]

On Thursday, 3 July 2025 at 21:56:03 UTC, kdevel wrote:
> ```d
> import std;
>
> extern (C) int sleep (int);
>
> void main ()
> {
>    defaultPoolThreads (8);
>    auto itemsstring = "a b c d e f g";
>    auto items = itemsstring
>       .split // split at ws
>       .filter!(s => s != "" && s[0] != '#')
> //      .array // uncomment for parallel execution
>       ;
>    pragma (msg, typeof (items));
>    foreach (item; parallel (items)) {
>       sleep (1);
>       writeln (item);
>    }
> }
> ```
>
> This program prints the letters a to g with a 1 s pause between 
> them.
> Is that intended?

likely, .array isnt aa's range code, ideally there would be a 
smarter "make a forward range more random access" primitive.