R SIG Debian - Dec 2021 - Open a text file with vi/vim in another Terminal

On Fri, 17 Dec 2021 21:13:12 +0100
Patrice Kiener <patrice.kiener at inmodelia.com> wrote:
> The instruction for the text editor
> 
>   system2(getOption("editor"), fileREP, wait = FALSE)
> 
> works fine on Windows (it opens Notepad.exe, or Notepad++.exe in my 
> Rprofile.site) but not on Unix. 
"A file.edit() but with the editor running in parallel with the R
session" is a hard problem.

Suppose that the user is running an R session on a server without a
graphical display over remote command line. The user is probably
running a graphical session with different windows, but R is unaware of
it; it's only got one text terminal. What should our hypothetical
file.edit.in.background() do in this case? It's fair to
stopifnot(interactive()), but this counts as an interactive session. In
theory, R could bundle a terminal multiplexer like tmux, split the
terminal window in half and emulate a smaller terminal for the editor
to run in, but there's no such functionality (or plans to implement it).

On Debian, there's the /usr/bin/x-terminal-emulator symlink (typically
present, but not 100% guaranteed to exist) pointing to _a_ graphical
terminal emulator (if you can assume a running graphical session), but
different terminal emulators take subtly different options to run
command lines inside them. For example, xterm runs the rest of the
command line after -e, while xfce4-terminal takes only one argument to
-e but the rest of the command line after -x. The result is that you
can't reliably pass arguments to the command you intend to launch. This
*could* be worked around by writing a temporary shell script in /tmp,
but the resulting solution accumulates too many moving parts to inspire
any confidence and doesn't work on other distros or macOS.

Besides, the user could plausibly prefer a text editor with a GUI when
running a graphical session. Can you ask your users to specify an
editor to run in the background? They could say it's 'emacs',
c('xterm',
'-e', 'joe'), c('xfce4-terminal', '-x',
'ed') or anything else.

What do you intend to do with the file being edited by the user?
Perhaps there's some other way to achieve the goal.

(Not sure whether it's a better question for R-help or R-pkg-devel.)

-- 
Best regards,
Ivan

On 18 December 2021 at 00:07, Ivan Krylov wrote:
| (Not sure whether it's a better question for R-help or R-pkg-devel.)

Agreed. There is nothing Debian-specific here, these are UI-musings which, as
discussed, are actually _hard_ if not impossible to solve in general.

(20 years I played with R's tcltk package as it was (and still is) the only
crossplatform tool allowing you to spawn a UI component on all OSs. And even
then it isn't installed everywhere [as it is optional on Windows with the
base R install] and will not work in pure "tty" text sessions.)

Dirk

-- 
https://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org