Allow multi-line editing in REPL

[Anton-4]

Some languages have multi-line editing using some special symbols to indicate another line is going to follow.
Others detect if what is entered is a parseble expression or statement, this could be a pain to implement.

My personal preference goes to Shift+Enter, which is commonly used to go to the next line without submitting when using text-areas.

I'll ask in the chat before implementing.

[ghigt]

Is it linked with #2666?

[Anton-4]

Yes indeed. Having this implemented would be a significant improvement in repl UX.

[Anton-4]

We use rustyline for generic repl features. This rustyline example adapted for Shift+Enter might be all that's needed. Are you interested in giving that a try @ghigt?

[ghigt]

Yes, I tried it before, but while this works

rl.bind_sequence(
    KeyEvent(KeyCode::Char('s'), Modifiers::CTRL),
    EventHandler::Simple(Cmd::Newline),
);

This is handled by the default Enter behavior:

rl.bind_sequence(
    KeyEvent(KeyCode::Enter, Modifiers::SHIFT),
    EventHandler::Simple(Cmd::Newline),
);

[Anton-4]

Oh I see, can you file an issue for that on the rustyline repo?

[ghigt]

kkawakam/rustyline#653

[Anton-4]

Thanks @ghigt!

[ghigt]

His response makes sens, do you think about an alternative?

[Anton-4]

Interesting, Ctrl+s is probably good.

[ghigt]

I don't want to enter into a battle 😇, but I associate Ctrl+s with "save", is there a particular reason that I don't know for the s key?

I would associate a newline with Ctrl+n or Ctrl+o (like in vim mode).

[Anton-4]

The main thing I like about Ctrl+s is that it is easy to reach single-handedly.

[lukewilliamboswell]

@Anton-4 recommend this be closed as completed. Just using enter on an expression that isn't complete seems to work fine.

% roc repl

  The rockin’ roc repl
────────────────────────

Enter an expression, or :help, or :q to quit.

» greeting : Str
… greeting = "Hi"

"Hi" : Str            # greeting

» 

[Anton-4]

Thanks for notifying me @lukewilliamboswell :)