[Rd] Is it advisable/possible to default on Linux to an EDITOR that actually exists?

[Michael Chirico]

Thanks Simon, I didn't know that! That's definitely a compelling
reason to leave the current default untouched and to eschew any
finicky attempts to find back-up editors.

Still, I think there is benefit from checking quickly that 'editor'
exists at run-time in file.edit() -- the current failure mode is
unusual (a shell error & R warning). Offering an R error would also
benefit, e.g., users with a typo in their custom EDITOR setting:

$ EDITOR=eamcs R
> file.edit(tempfile())
# /bin/sh: line 1: eamcs: command not found
# Warning message:
# error in running command

Where I come up short is knowing the platform-robust way to implement
this -- nzchar(Sys.which(editor)) looks like it will work fine on
Unix, but I don't know what to do about macGUI/Windows.

Mike C


On Wed, Dec 11, 2024 at 9:31 AM Simon Urbanek
<simon.urbanek using r-project.org> wrote:
>
> Michael,
>
> vi is the only editor that is part of the POSIX standard. Embedded systems have built-in support only for vi (e.g., busybox) so if a system has any editor support at all it is  most likely to be vi - it is ubiquitous which is why it's the most logical default. (FWIW no distributions I know come with emacs by default because it's too heavy, but all come with vi).
>
> If you use stripped-down images (obviously no longer standards-compliant) then you don't have any editor so it's moot. If you have preference for another editor then you should set EDITOR or VISUAL - it's just a default when neither the system nor user doesn't declare their preference. I don't think R should be fishing for random programs that may or may not be editors at run-time.
>
> Cheers,
> Simon
>
>
> > On Dec 11, 2024, at 5:08 AM, Michael Chirico <michaelchirico4 using gmail.com> wrote:
> >
> > It looks like R has defaulted to using 'vi' for file.edit() (via
> > EDITOR since ~24 years ago[1][2].
> >
> > These days I think it is much more common to write code from
> > lightweight environments, e.g. Docker files which strip all
> > unnecessary commands. On such machines, it is not safe to assume 'vi'
> > is installed, and it's not uncommon to encounter an issue like I did
> > again today[3] where you or some other tool call file.edit() directly
> > or implicitly and hit a clunky error.
> >
> > Is there something better to do here? A "standard" Linux distribution
> > will come with vi, emacs, nano, probably many others. Should
> > `file.edit()` iterate over an ordered list to find the first that
> > exists? Should it at least error if
> > (!nzchar(Sys.which(Sys.getenv("EDITOR"))))?
> >
> > Mike C
> >
> > PS I do see some somewhat recent discussion[4] on EDITOR but it
> > focuses on the EDITOR default in non-interactive() sessions.
> >
> > [1] https://github.com/r-devel/r-svn/commit/b294ee2cef3d9292d578b062b80d59f372cf34b2#diff-1cbaac4768fd110525ba9086cb7a684aaf2c6555389c5446c913effbfec90c85
> > [2] https://github.com/r-devel/r-svn/blob/71a2e968f4453858aadc1531a3774c011a6f9f49/doc/NEWS.0#L140-L141
> > [3] https://github.com/r-lib/usethis/pull/2088
> > [4] https://stat.ethz.ch/pipermail/r-devel/2023-July/082720.html
> >
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