poly-markdown+r-mode doesn't like ESS evaluation commands? about polymode

[vspinu]

I will solve this some day in a general, non ESS specific, way. For time
being, please add empty lines before and after the code.

On 29 July 2013 06:29, Peter Meilstrup [email protected] wrote:

Open an .Rmd file and type in

testing...

x <- function() {
  1
}

Position cursor in the function and type C-c C-c, C-c C-p, or such. It
tries to evaluate the lines with the backticks along with the lines
belonging to the function.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/6
.

[troyac]

This works for me:

(defun Rmd-setup ()
  (setq paragraph-start "```\\|\\s-*$")
  (setq paragraph-separate "```\\|\\s-*$"))

(add-hook 'poly-markdown+r-mode-hook 'Rmd-setup)

[plantarum]

I encountered a related issue trying to evaluate functions from within fenced code blocks. The backticks in the fences, or apostrophes in the preceding markdown chunk, will make ESS think it is inside a string, and so refuse to evaluate the code. A possible approach to fixing this issue, and the one that @crowding raised, is the following advice:

EDITED Jan 27 - forgot the else clause!

(defun pm-ess-limit-eval-to-chunk (orig-fun &rest args)
  "Wrapper for ess-eval-functions.
Without this, apostrophes in the preceding text chunk cause
ess-mark-function, ess-send-function to fail, thinking they are inside a
string. Similarly, ess-eval-paragraph gets confused by the fence rows."
  (interactive)
  (let (res)
    (if poly-markdown+r-mode
        (save-restriction
          (pm/narrow-to-span)
          (setq res (apply orig-fun args)))
      (setq res (apply orig-fun args)))
    res))

(advice-add 'ess-beginning-of-function :around #'pm-ess-limit-eval-to-chunk)
(advice-add 'ess-eval-paragraph :around #'pm-ess-limit-eval-to-chunk)

Since this code will only modify the behaviour of the functions in question from within polymode, it should be safe to apply generally. However, there may be better solutions than global advice? If not, I can wrap this up in a pull request.