Partial application on Nth argument

[monkyyy]

On Wednesday, 4 December 2024 at 08:50:21 UTC, axricard wrote:
> Hello
>
> I believe std.functional.partial can only apply to the first 
> argument.
> Is there an equivalent for the Nth argument ?
>
> Something like :
>
> ``` D
> int fun(int a, int b) { return a - b; }
>
> // create a function with the argument n°1 being equal to 5
> // fun5 = fun(a, 5);
> alias fun5 = partialN!(fun, 1, 5);
> writeln(fun5(7)); // print 2
> ```

nothin Im aware of in the std but I think this is trivail

```d
import std;
template partialN(alias F,int arg,argvalue...){
	auto partialN(T...)(T 
otherargs)=>F(otherargs[0..arg],argvalue[0],otherargs[arg..$]);
}
unittest{
	int fun(int a, int b) { return a - b; }
	// create a function with the argument n°1 being equal to 5
	// fun5 = fun(a, 5);
	alias fun5 = partialN!(fun, 1, 5);
	writeln(fun5(7));
}
```