I thought I needed something like staticIota in a unittest to effect static foreach over a number range and I found one in druntime's implementation:


https://github.com/dlang/druntime/blob/master/src/core/internal/traits.d#L106

(I wonder why that one is implemented in divide-and-conquer fashion. Perhaps due to faster compilation that way?)

Then I realized that this is actually pretty easy with D:

template staticIota(size_t N) {
    import std.range: iota;
    import std.meta: aliasSeqOf;
    alias staticIota = aliasSeqOf!(N.iota);
}

unittest {
    size_t count = 0;
    foreach (i; staticIota!10) {
        mixin("++count;");
    }
    assert(count == 10);
}

void main() {
}

I realized that I don't actually need it but I wanted to share. :)

Ali

P.S. Related, I've been using D for a living since I started working for Weka.IO in June. (I think the only mention of that was in this blog post: https://dlang.org/blog/2016/06/). The more I use D, the more I like it but you already know it. ;)

On Friday, 9 December 2016 at 18:52:59 UTC, Ali Çehreli wrote:
> I thought I needed something like staticIota in a unittest to effect static foreach over a number range and I found one in druntime's implementation:
>
>
> https://github.com/dlang/druntime/blob/master/src/core/internal/traits.d#L106
>
> (I wonder why that one is implemented in divide-and-conquer fashion. Perhaps due to faster compilation that way?)
>

Yes it is.
n log n
instead of n^2

On 12/09/2016 05:34 PM, Stefan Koch wrote:
> On Friday, 9 December 2016 at 18:52:59 UTC, Ali Çehreli wrote:
>> I thought I needed something like staticIota in a unittest to effect
>> static foreach over a number range and I found one in druntime's
>> implementation:
>>
>>
>> https://github.com/dlang/druntime/blob/master/src/core/internal/traits.d#L106
>>
>>
>> (I wonder why that one is implemented in divide-and-conquer fashion.
>> Perhaps due to faster compilation that way?)
>>
>
> Yes it is.
> n log n
> instead of n^2
>

Makes sense. I was stopping my counting at n: both looked O(n) to me. :)

How about my staticIota()? Is it n^2 inside the compiler?

Ali

On Saturday, 10 December 2016 at 01:48:24 UTC, Ali Çehreli wrote:
> On 12/09/2016 05:34 PM, Stefan Koch wrote:
>> On Friday, 9 December 2016 at 18:52:59 UTC, Ali Çehreli wrote:
>>> I thought I needed something like staticIota in a unittest to effect
>>> static foreach over a number range and I found one in druntime's
>>> implementation:
>>>
>>>
>>> https://github.com/dlang/druntime/blob/master/src/core/internal/traits.d#L106
>>>
>>>
>>> (I wonder why that one is implemented in divide-and-conquer fashion.
>>> Perhaps due to faster compilation that way?)
>>>
>>
>> Yes it is.
>> n log n
>> instead of n^2
>>
>
> Makes sense. I was stopping my counting at n: both looked O(n) to me. :)
>
> How about my staticIota()? Is it n^2 inside the compiler?
>
> Ali

it's O(n log n)*((n!)/some_really_large_number)

Because the template-subsystem is it not really build for a abuse like AliasSeq.
After a cut-off point the factorial factor will dominate.