Ruby-style "each" in D?

[Andrea Fontana]

On Thursday, 20 March 2014 at 15:02:46 UTC, Simen Kjærås wrote:
> On 2014-03-20 14:16, Andrea Fontana wrote:
>> On Thursday, 20 March 2014 at 12:32:49 UTC, w0rp wrote:
>>> // std.parallelism parallel function here.
>>> someRange.whatever.parallel(numberOfUnits).each!doSomething
>>
>> +1
>>
>> This works:
>> foreach(i; [0,1,2,3,4,5].parallel) i.writeln;
>>
>> This works:
>> [0,1,2,3,4,5].each!writeln;
>>
>> This won't compile:
>> [0,1,2,3,4,5].parallel.each!writeln;
>>
>> Error: template tmp.each cannot deduce function from argument 
>> types
>> !(writeln)(ParallelForeach!(int[])), candidates are:
>> /tmp/tmp.d(9):        tmp.each(alias fun, Range)(Range range) 
>> if
>> (isInputRange!Range)
>
>
> It could be made to work, though:
>
> template isIterable(T) {
>     enum isIterable = is(typeof((T t){foreach (e; t){}}));
> }
>
> template isRefIterable(T) {
>     enum isRefIterable = is(typeof((T t){foreach (ref e; 
> t){}}));
> }
>
> void each(alias fun, Range)(Range range)
>     if (isInputRange!Range)
> {
>     while (!range.empty)
>     {
>         unaryFun!fun(range.front);
>         range.popFront();
>     }
> }
>
> void each(alias fun, Range)(Range range)
>     if (!isInputRange!Range && isRefIterable!Range)
> {
>     foreach (ref e; range) {
>         unaryFun!fun(e);
>     }
> }
>
> void each(alias fun, Range)(Range range)
>     if (!isInputRange!Range && isIterable!Range && 
> !isRefIterable!Range)
> {
>     foreach (e; range) {
>         unaryFun!fun(e);
>     }
> }
>
> void main() {
>     [0,1,2,3,4,5].parallel.each!writeln;
> }
>
> --
>   Simen

I think that pull request should be updated.

Why isn't ParallelForEach implemented as Range, instead?