ocaml-tui / tty Goto Github PK

As it stands now, there's a few flags that are always false in profile.ml

  (* TODO(@leostera): String.contains "256color" "color" "ansi" *)
  let is_256color = false in
  let is_color = false in
  let is_ansi = false in

The checks for these are essentially String.contains checks, and need to be done based on the env variables available.

I've been trying to figure out a way to get the dimensions of the current terminal in a sensible (somewhat) cross-platform way. I thought it'd be a fairly easy thing to do and I could try submitting a PR once I have something working, but it's proving to be beyond my skill/knowledge level with OCaml and terminals in general.

However, it seems like a very common thing that people would expect to see in a library like this, so I figured it could merit some discussion at the very least?

AFAIK there's a bunch of ways it could be done, but they all have downsides:

• CSI DSR (\x1b[6n) should cause a status message ESC[n;mR to be 'printed' to STDIN. I got this kind of working¹, but this only seems to work for certain terminals. Foot, Alacritty, URXVT and the linux console worked for me while Kitty, Wezterm, xfce-terminal and, surprisingly, xterm didnt.
• ioctl() through Ctypes works, kind of², but I could not figure out a way to access libc constants in OCaml, so I had to hardcode the value of TIOCGWINSZ, so it's the furthest thing from cross platform.
• A separate mini-library that just exposes a couple functions to get the terminal size. Probably the most cross-platform and easiest method, but I didn't try it because submitting a PR with a bunch of C seemed like it might not be welcome. If I'd gone with this method, I'd be tempted to do some of the terminal setup/cleanup through C as well, just because IIRC dealing with things like SIGWINCH, SIGINT etc. in OCaml is much harder(?)
• tputs and/or stty - shelling out to these seems like an easy 'cheat' but I doubt these are available on all platforms.

I think the Stdin module should read from /dev/tty instead of stdin (or else the user should be able to choose). Otherwise writing interactive programs that read input from stdin (e.g. fzf in cat ... | fzf) will have problems.

Specifically, when I tried doing that with minttea, I got an ENOTTY error message (although the program still seemed to function as expected). Changing the stdin module to start with let stdin_fd = Unix.descr_of_in_channel (In_channel.open_bin "/dev/tty") got rid of it.