How to pass Vec<String> or &[String]

[happydpc]

I want to expose a this-like function to cpp. But id can't.

pub fn test(&self, s: &Vec<String>) {}

[Dushistov]

There is no predefined type conversations for this.
Mostly because of because of it need bunch of extra code for this specific case.

One way to handle this is:

type VecOfStrings = Vec<String>;

foreign_class!(
    class VecOfStrings {
        self_type VecOfStrings;

        constructor default() -> VecOfStrings {
            Vec::<String>::default()
        }

        fn at(&self, i: usize) -> &str {
            this[i].as_str()
        }
    }
);

fn test(s: &Vec<String>) {
    unimplemented!()
}

foreign_class!(
class WorkWithStrings {
    fn test(s : &VecOfStrings);
}
);

[happydpc]

Thank you for your reply. It's very useful.

[35359595]

is there a plan to implement this? quite common scenario to have this type of param...

[stephan57160]

I was about to raise another issue for the same, and I have the same question.
Any plan to implement this ?
Maybe with some help ?

[Dushistov]

Any plan to implement this ?

No specific plans for this. I my practice I need it twice, one time I use work around mentioned here, other time I wrote rule to convert Vec<String> to QStringList. But I doubt that these two variants may be used as general solution.

Maybe with some help ?

For now for C++ there are support of Vec of "primitive type" (can be generalized to any #[repr(C)] type),
and Vec of "foreign class". The great addition would be Vec of already mapped to C++, but not foreign class and not primitive type.
But not sure that this is possible.

[stephan57160]

But I doubt that these two variants may be used as general solution.
Maybe not.
But, in case, a CppQStringList could help, like it's done for CppVariant or others.

The great addition would be Vec of already mapped to C++, but not foreign class and not primitive type.
Hmmm...
I'm pretty fresh to Rust and Flapigen, so ... not sure to understand what you have in mind...

[Dushistov]

The great addition would be Vec of already mapped to C++, but not foreign class and not primitive type.
I'm pretty fresh to Rust and Flapigen, so ... not sure to understand what you have in mind...

flapigen can works with generic rules, for now there are two generic rules for slices:

($p:r_type) <T: SwigForeignClass> &[T] => CRustObjectSlice

and

($p:r_type) <T: SwigTypeIsReprC> &[T] => CRustSlice!() {

So if somebody add the third rule, without any trait contrait
in theory it should match all types like: &[String] and &[Vec<i32>],
so it is possible to create generic rules for them.