Printing a range of ranges drains them

[Salih Dincer]

On Monday, 27 May 2024 at 06:31:37 UTC, Jonathan M Davis wrote:
> ...
> Given that writeln needs to work with basic input ranges, 
> having it not consume the inner ranges would result in 
> different behavior between basic input ranges and forward 
> ranges, which wouldn't be great. So, arguably, having it 
> consume them is the correct choice, but I'd have to spend a 
> fair bit of time thinking through the implications to come to a 
> properly informed conclusion.
> ...


It is possible to show the same situation with iota() and of 
course if this is a contradictory situation:

```d
alias strings = char[][];
enum form = "[%(%s, %)]";
void main()
{
     auto num = iota(1, 4);
     auto range = [num, num, num];

     write("[ ");
     foreach(rng; range)
       rng.write(" ");
     writeln("]");

     range.writefln!form;
     range.writefln!form;

     strings str;
     auto s = "123".dup;
     str = [s, s, s];

     str.writefln!form;
     str.writefln!form;
} /*

    [ [1, 2, 3] [1, 2, 3] [1, 2, 3] ]
    [[1, 2, 3], [1, 2, 3], [1, 2, 3]]
    [[], [], []]
    ["123", "123", "123"]
    ["123", "123", "123"]

//*/
```

When we do the same experiment with the strings above, we get 
different results. Moreover, foreach() similarly does not consume 
the inner ranges...

Now there is a contradiction on the writeln() side!

SDB at 79