Re: How to unpack template parameters,Or how to forward parameters?

[zjh via Digitalmars-d-learn]

On Friday, 6 May 2022 at 05:44:39 UTC, vit wrote:


Try this:


Very Good,Thank you very much!

Re: How to unpack template parameters,Or how to forward parameters?

[vit via Digitalmars-d-learn]

On Friday, 6 May 2022 at 00:41:18 UTC, zjh wrote:

Hello everyone,I have following function:
```d
import core.stdc.stdio;
void f(int i,int j){
printf("%i,%i",i,j);
}
```
I want to forward `int[N]` to `(int i,int j)` etc. How can I 
write a forwarding function?

```d
void ff(alias g,int...I)(int[2]k){
g(k[I]);
}//How to unpack template variable parameters?

void f(int[2]k){
ff!(f,0,1)(k);//how to forward?
}

```

main function:
```d
extern(C):void main()
{
int[2] a=[2,4];
f(a);//calling like this
}
```


Try this:

```d
import core.stdc.stdio;

void f(int i,int j){
printf("%i,%i",i,j);
}


import std.range :  iota;
import std.traits :  isStaticArray;
import std.meta :  AliasSeq;


template expand(alias arr)
if(isStaticArray!(typeof(arr))){
auto get(size_t I)(){
return arr[I];
}

alias Result = AliasSeq!();

static foreach(I; iota(0, arr.length))
Result = AliasSeq!(Result, get!I);

alias expand = Result;
}


extern(C):void main(){
int[2] a=[2,4];
f(expand!a);
}
```