Re: No static fold 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
Re: No static fold in phobos ?
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]);
}
Re: No static fold in phobos ?
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...
No static fold in phobos ?
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 ?
