[WIP] tty: Deno.stdin.setRaw()

[kevinkassimo]

Basic implementation of raw mode for stdin. Implementation is tentative (op names unsure), and code is mostly lifted from crossterm or rustyline (without introducing more deps)

Likely won't work properly on Windows since I cannot test it locally.

// Returns a function that when called, restores original mode.
// I do not want to expose other tty flags, so this hides away the flags' existence
let restore = Deno.stdin.setRaw();
restore = Deno.stdin.setRaw(); // Safe to call again before restore.

const buf = new Uint8Array(6);
for (let i = 0; i < 6; i++) {
  const nread = await Deno.stdin.read(buf);
  if (nread === Deno.EOF) {
    break;
  } else {
    console.log(`READ ${nread} bytes:`, new TextDecoder().decode(buf.subarray(0, nread)));
  }
}

restore(); // restores old mode. Can be safely called multiple times
restore(); // safe to call multiple times

Sample run (assume imput is is raw):

$ ./target/debug/deno raw_mode.ts
READ 1 bytes: i
READ 1 bytes: s
READ 1 bytes:
READ 1 bytes: r
READ 1 bytes: a
READ 1 bytes: w

[ry]

Looks pretty good! Nice work! I'm adding @piscisaureus to review because I think he has some specific ideas about how TTY APIs should look.

[ry]

We need to add their copyright header to this file. Something like this

// Copyright (c) 2015 Katsu Kawakami & Rustyline authors. MIT license.

[kevinkassimo]

Also #3958 over option 2

[kevinkassimo]

Closed in favor of #3958