How to force evaluation of range?

[Xinok via Digitalmars-d-learn]

On Saturday, 13 February 2016 at 03:16:09 UTC, cym13 wrote:
> On Saturday, 13 February 2016 at 02:17:17 UTC, Xinok wrote:
>> On Friday, 12 February 2016 at 20:43:24 UTC, Taylor Hillegeist 
>> wrote:
>>> So I have this code and I have to add the element
>>> .each!(a => a.each!("a"));
>>> to the end in order for it to evaluate the range completely 
>>> and act like I expect it too. Is there a  better thing to put 
>>> in the place of
>>> .each!(a => a.each!("a"));?
>>>
>>> ...
>>
>> The following combination might work:
>>
>> .joiner.each;
>>
>> http://dlang.org/phobos/std_algorithm_iteration.html#.joiner
>>
>> http://dlang.org/phobos/std_algorithm_iteration.html#.each
>
> Why not just  .each;   ?

The thing he's trying to iterate over is a range of ranges. A 
single .each will only iterate over the outermost range so you 
need .joiner first to "flatten" the range, then you can use .each 
on that result.