RFC: getKey vs getKeys

[inv2004]

Initial example in readme:

while true:
  var key = getKey()
  case key
  of Key.None: discard
  of Key.Escape, Key.Q: exitProc()
  else:
    tb.write(8, 4, ' '.repeat(31))
    tb.write(2, 4, resetStyle, "Key pressed: ", fgGreen, $key)

  tb.display()
  sleep(20)

[inv2004]

getKeys example:

while true:
  for key in getKeys():
    case key
    of Key.None: discard
    of Key.Escape, Key.Q: exitProc()
    else:
      tb.write(8, 4, ' '.repeat(31))
      tb.write(2, 4, resetStyle, "Key pressed: ", fgGreen, $key)

  tb.display()
  sleep(20)

[inv2004]

getKey with buffer example:

Not sure if display should be in the inner while loop or not

while true:
  var key = getKey()
  while key != Key.None:
    case key
    of Key.None: discard
    of Key.Escape, Key.Q: exitProc()
    else:
      tb.write(8, 4, ' '.repeat(31))
      tb.write(2, 4, resetStyle, "Key pressed: ", fgGreen, $key)
    key = getKey()

  tb.display() 
  sleep(20)

[johnnovak]

getKey with buffer example:

Yeah, so this is how I want the API to look like, getKeys is an unnecessary complication.

[inv2004]

Don't you think the double while loop looks not obvious and even ugly? Also, it is just iterator over while simulation.

[johnnovak]

Don't you think the double while loop looks not obvious and even ugly? Also, it is just iterator over while simulation.

I want to have a minimal API surface. If you really want getKeys(), you can trivially implement it in your code.

Also, you don't need a double while loop if you don't particularly care about 20ms delay between processing keypresses now and then. Or you can do 5 or 10ms sleep. Again, up to the client code how to deal with this, the minimum we need is getKey.

[inv2004]

The only good, in my opinion, solution to avoid the cpu usage and to avoid sleep without any delays is:

while true:
  let key = getKeyWithTimeout(1000)
  case key
  of Key.None:
    buf.add '.'
  of Key.Escape, Key.Q: exitProc()
  else:
    buf.add $key
  if buf.len > 20:
    buf = buf[^20..^1]
  tb.write(8, 4, ' '.repeat(31))
  tb.write(2, 4, resetStyle, "Key pressed: ", fgGreen, buf)
  tb.display()

[johnnovak]

Thanks for the examples @inv2004, but I've said all I wanted on the matter. getKeyWithTimeout is against my vision how an immediate mode UI API should operate.

I only want getKey, and getKeys needs to become private. If you feel like making the change, a PR is welcome, otherwise I will do it in the coming days.

Thank you.

[johnnovak]

Actually @inv2004, thought about it a bit more and getKeyWithTimeout(20) or something could work, yeah. Your 1000 ms wait time just threw me off ;) If you want to work on this, I'm happy for you to introduce getKeyWithTimeout in addition to getKey. Then people can decide which one to use.

[inv2004]

I am working on getKeyWithTimeout

When it is ready - getKeys can be rolled back

The main challenge is to avoid any addition buffers and to make parser for long sequences works directly on stdin next char

[johnnovak]

@inv2004 Please make sure that your async solution works not only in Linux terminals but also on Windows in CMD.EXE and on macOS. All illwill features need to be cross-platform. I don't have much time and interest to figure this out, so getKey + sleep is always the fallback option if you can't do Windows & macOS 😏

[inv2004]

Done here https://github.com/johnnovak/illwill/pull/47

• [x] Linux stdin parser
• [x] some small tests for the parser
• [x] Windows did not work correct at all even before the change => fixed and changed

BTW: win api looks 10 times better than the stdin escapes

-- added -- Please check macos by yourself

[inv2004]

Here is an iterator for someone who wants pretty monotonic ticks without sleep:

iterator keyEachSec(): Key =
  var timeout = 1000
  while true:
    let a = getMonoTime().ticks
    let k = getKeyWithTimeout(timeout)
    if k == Key.None:
      timeout = 1000
    else:
      let b = int((getMonoTime().ticks - a) div 1000000)
      timeout = timeout - (b mod 1000)
    yield k