That would work on an AliasSeq ?
I'm surprised not to find one:

eg:

~~~~~~~
enum seq = AliasSeq!("aa", "bb");
enum val = staticFold!((a,b)=>a~b, seq);
static assert(val == "aabb");
~~~~~~~

it works with foreach or a eponymous template that consumes the sequence , but as said where is it in phobos ?

On 11/27/2015 12:57 PM, userabcABC123 wrote:
> That would work on an AliasSeq ?
> I'm surprised not to find one:
>
> eg:
>
> ~~~~~~~
> enum seq = AliasSeq!("aa", "bb");
> enum val = staticFold!((a,b)=>a~b, seq);
> static assert(val == "aabb");
> ~~~~~~~
>
> it works with foreach or a eponymous template that consumes the sequence
> , but as said where is it in phobos ?

Thanks to CTFE, there is usually no need for static of anything in D. Your code works with a few changes:

import std.meta;
import std.algorithm;

void main() {
    enum seq = AliasSeq!("aa", "bb");
    enum val = [ seq ].reduce!((a, b) => a ~ b);
    static assert(val == "aabb");
}

Ali

On Friday, 27 November 2015 at 20:57:44 UTC, userabcABC123 wrote:
> That would work on an AliasSeq ?
> I'm surprised not to find one:
>
> eg:
>
> ~~~~~~~
> enum seq = AliasSeq!("aa", "bb");
> enum val = staticFold!((a,b)=>a~b, seq);
> static assert(val == "aabb");
> ~~~~~~~
>
> it works with foreach or a eponymous template that consumes the sequence , but as said where is it in phobos ?

There's not much sense in a staticFold template that takes a function literal, as you can use regular functions in D at compile time. However, you need to use template "functions" for some things, so here's a simple way to do that:

template staticFold(alias f, List...)
if (List.length > 1)
{
	static if (List.length == 2)
	{
		alias staticFold = f!(List[0], List[1]);
	}
	else
	{
		alias staticFold = staticFold!(f, f!(List[0], List[1]), List[2..$]);
	}
}

enum cat(alias l, alias r) = l ~ r;

void main()
{
	assert(staticFold!(cat, [0], [1]) == [0, 1]);
	assert(staticFold!(cat, [0], [1], [2]) == [0, 1, 2]);
	assert(staticFold!(cat, [0], [1], [2], [3]) == [0, 1, 2, 3]);
	assert(staticFold!(cat, [0], 1, 2, 3, 4) == [0, 1, 2, 3, 4]);
}

On Friday, 27 November 2015 at 23:46:32 UTC, Ali Çehreli wrote:
> On 11/27/2015 12:57 PM, userabcABC123 wrote:
>> That would work on an AliasSeq ?
>> I'm surprised not to find one:
>>
>> eg:
>>
>> ~~~~~~~
>> enum seq = AliasSeq!("aa", "bb");
>> enum val = staticFold!((a,b)=>a~b, seq);
>> static assert(val == "aabb");
>> ~~~~~~~
>>
>> it works with foreach or a eponymous template that consumes the sequence
>> , but as said where is it in phobos ?
>
> Thanks to CTFE, there is usually no need for static of anything in D. Your code works with a few changes:
>
> import std.meta;
> import std.algorithm;
>
> void main() {
>     enum seq = AliasSeq!("aa", "bb");
>     enum val = [ seq ].reduce!((a, b) => a ~ b);
>     static assert(val == "aabb");
> }
>
> Ali

Thx, so the trick was to pack seq in something that's a range...