[ESS] Failure to parse long R functions when ess-eval-visibly nil

[Vitalie Spinu]

This is a known problem with ess-remote. I have no idea why the characters are
lost. It's some emacs shell bug which I couldn't figure out last time I looked
into it. This problem is almost impossible to reproduce consistently and debug
properly.

I suggest you stick with tramp. This problem never occurs with tramp and you
have full set of ESS features on remotes, while ess-remote provides only a very
limited functionality.

  Vitalie

>> On Wed, Oct 07 2015 13:47, Robert McGehee wrote:

> Hello,
> I'm having an issue in which sufficiently long and complex functions will
> fail to correctly evaluate in R (with e.g. ess-eval-function) if
> ess-eval-visibly is nil rather than true. Instead I receive syntax errors
> part way through the function that seem to indicate that a line or
> character was accidentally dropped during the ess eval making the function
> un-parsable. If I turn on visibility (ess-eval-visibly t), the problem
> disappears but the evaluation takes a long time due to latency on my setup.
> Moreover, the problem isn't perfectly reproducible as the syntax error will
> occur somewhat at random. However, with a sufficiently long and complex
> function (e.g. 300+ lines) I'm virtually guaranteed an error.

> Unfortunately, my setup is likely unusual so I'm not sure if this is an ESS
> error. However, I wanted to post in case anyone had any ideas on a fix
> (besides just turning ess-eval-visibly to true).

> For my setup, I run emacs 24.5.1 on my local (USA) Windows box via Cygwin
> and have ESS 15.09 installed from source. I connect to a remote (European)
> Linux server via emacs shell and ssh, then start R (3.2.2) and start
> ESS-mode with M-x ess-remote. I run emacs locally rather than on the server
> side as I'm connecting to a server across the Atlantic ocean and latency is
> too high for X11 forwarding. Additionally, given the latency, I have to
> wait a considerable amount of time to eval an R function visibly, whereas
> it happens extremely fast if I turn off visible eval. Thus, I'd much prefer
> a working non-visible eval.

> Here's a simple function I used to generate the syntax error. It has the
> advantage of nearly guaranteeing a parsing failure if any character is
> missing.

> a <- function(x) {
>     if (a(b,"c"))
>         x <- d(e(f(g,"H"),"I"),"J",k="L")
>     if (a(b,"c"))
>         x <- d(e(f(g,"H"),"I"),"J",k="L")
> <...snip... repeated ~300 times>
>     if (a(b,"c"))
>         x <- d(e(f(g,"H"),"I"),"J",k="L")
> }

> ## Here is the error I got indicating two closing parentheses "))" were
> dropped during eval:
> Error: unexpected symbol in:
> "    if (a(b,"c"
>         x"

> (Possibly unrelated, if any line has two consecutive tab characters, then
> ESS will actually print the contents of the home directory of the remote
> server, which is exceptionally weird.)

> Please let me know if anyone has any thoughts on this. Otherwise I'll just
> turn ess-eval-visibly back to true.

> Thanks!
> Robert

> PS.
> Here is the relevant portion of my .emacs file:

> (require 'cl)
> (load "cc-mode")
> (load "compile")

> (require 'ess-site)
> (setq comint-scroll-to-bottom-on-input t)
> (setq comint-scroll-to-bottom-on-output t)
> (setq ess-eval-visibly nil)
> (setq ess-nuke-trailing-whitespace-p t)
> (setq-default ess-directory "/tmp/")
> (define-key key-translation-map [?\C-h] [?\C-?])

> (transient-mark-mode t)
> (setq display-time-day-and-date t)
> (display-time-mode 1)
> (setq visible-bell t)
> (setq undo-outer-limit 100000)

> (setq line-number-display-limit nil)
> (setq line-number-display-limit-width 2000)
> (setq column-number-mode t)
> (require 'paren)
> (if (fboundp 'show-paren-mode) (show-paren-mode 1))

> (setenv "PID" nil)
> (put 'upcase-region 'disabled nil)
> (add-hook 'ess-mode-hook
>       (lambda ()
>         (ess-set-style 'C++ 'quiet)
>         (add-hook 'local-write-file-hooks
>               (lambda ()
>             (ess-nuke-trailing-whitespace)))))
> (setq truncate-partial-width-windows nil)

> 	[[alternative HTML version deleted]]

> ______________________________________________
> ESS-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/ess-help