Implement Input for Iterator<Item = Input>

[soenkehahn]

I recently wanted to pass std::env::args().skip(1) to a child process. So I did std::env::args().skip(1).collect::<Vec<_>>(). Maybe there should be an easier way to pass in iterators?

[casey]

I think we would need a wrapper type, since we can't due blanket impls due to the impl on &I where I: Input.

This works:

struct Inputs<I: IntoIterator<Item = T>, T: Input>(I);

impl<I: IntoIterator<Item = T>, T: Input> Input for Inputs<I, T> {
    fn configure(self, config: &mut Config) {
        for input in self.0 {
            input.configure(config);
        }
    }
}

#[test]
fn can_pass_multiple_inputs_with_inputs() {
    let crate::StdoutTrimmed(s) = crate::run_output!("echo", Inputs(vec!["a", "b", "c"]));
    assert_eq!(s, "a b c");
}

[soenkehahn]

Yeah, I was also thinking that a wrapper type might be necessary.

Out of curiosity, what exactly is the advantage of using IntoIterator over Iterator here?

[casey]

Out of curiosity, what exactly is the advantage of using IntoIterator over Iterator here?

Usually, Iterator is implemented by a specialized iterator types, for example std::vec::Iter or std::collections::hash_map::Keys. Vec and HashMap themselves instead implement IntoIterator to return an iterator.