EOF should maybe yield ReadlineError::Eof instead of just terminating Editor::iter

[MultisampledNight]

Context

I'm using using rustyline for the first time in a situation like this:

    rl.iter(" > ").try_for_each(|line| {
        // ...
        let result = match line {
            Ok(line) => process_line(line),
            Err(Eof | Interrupted) => Err(Exit), // user wants to abort normally, fine
            Err(err) => Err(Fatal(err)),         // help
        };
        // ...
    });

I wanted to bind both Ctrl-D and Ctrl-C to exiting, as my program isn't hosting anything else it could reach out to for processing the interrupt. But to my surprise, it seems like Eof is never emitted when using Editor::iter, it just plainly ends the iterator. I'd have expected it to be a constant stream of events.

Suggestions

• Make the iterator yielded by Editor::iter infinite, while providing ReadlineError::Eof as a normal "error". (I'd be open to implement that and open a PR, if wanted)
• If ^ is not a viable option for whatever reason, document in Editor::iter logical OR in ReadlineError::Eof the special case of when the iterator terminates.

Minimal reproducable code example

Relying on rustyline 10.0.0

use rustyline::{error::ReadlineError, Editor};

fn main() {
    let mut rl = Editor::<()>::new().unwrap();

    for line in rl.iter("pls hit ctrl-d> ") {
        match line {
            Err(ReadlineError::Eof) => unreachable!("I want to get here"),
            Err(ReadlineError::Interrupted) => {
                unreachable!("This is also a real error though it technically isn't")
            }
            Err(err) => panic!("irrelevant: {}", err),
            Ok(_) => panic!("please do enter ctrl-d"),
        }
    }

    println!("done! :sparkles:");
}

[gwenn]

https://github.com/kkawakam/rustyline/blob/master/src/lib.rs#L942
The iterator currently behaves like a line iterator on a file: the iterator ends at end of file.

[gwenn]

Like https://python-prompt-toolkit.readthedocs.io/en/master/pages/tutorials/repl.html?highlight=iterate#loop-the-repl

[MultisampledNight]

Yep, I get the current behavior. I'd love to have some documentation shine light on this behavior though, or allow it to be handled specifically by yielding Eof instead of just terminating.

[gwenn]

For me, the line iterator becomes useless without the EOF condition: just use a loop.
But yes, this should be documented.

[MultisampledNight]

Alright. Thank you!