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
```
Why does 'alias' take 3 parameters? Maybe I'm misunderstanding,
but this is what you want:
```d
template partialN(alias func, int idx, args...)
{
enum error = "Missing argument!";
static assert(idx < args.length, error);
auto partialN(T)(T first)
{
return func(first, args[idx]);
}
} unittest {
auto sum = (int a, int b) => a + b;
alias sum11= partialN!(sum, 1, 10, 11, 12);
assert(sum11(9) == 20);
alias sum12= partialN!(sum, 2, 10, 11, 12);
assert(sum12(9) == 21);
auto and = (bool a, bool b) => a & b;
alias and11= partialN!(and, 1, false, true, false);
assert(and11(true));
}
```
SDB@79
