[ESS] Inserting Rmd chunk delimiters

[Laurent Gatto]

I have defined the following functions:

(defun insert-md-code-chunk ()
  "Insert Rmd code chunk"
  (interactive)
  (insert "```\n\n```")
  (backward-char 4))

(defun insert-rmd-code-chunk ()
  "Insert Rmd code chunk"
  (interactive)
  (insert "```{r}\n\n```")
  (backward-char 4))

(defun insert-rnw-code-chunk ()
  "Insert Rnw code chunk"
  (interactive)
  (insert "<<>>=\n\n@")
  (backward-char 2))

(defun insert-org-code-chunk ()
  "Insert Rnw code chunk"
  (interactive)
  (insert "#+BEGIN_SRC R :session *R*\n\n#+END_SRC")
  (backward-char 10))


(defun insert-code-chunk ()
  "Insert appropriate code chunk based on buffer extension"
  (interactive)
  (pcase (file-name-extension (buffer-file-name))
    (`"Rnw" (insert-rnw-code-chunk))
    (`"org" (insert-org-code-chunk))
    (`"Rmd" (insert-rmd-code-chunk)) 
    (`"md" (insert-md-code-chunk)) 
    (code (message "Unknown buffer extension"))))


and bound the last one to C-c, which then inserts the appropriate code
chunks delimiters in Rnw, org, Rmd and md file. Comments most welcome.

Best wishes,

Laurent


On 20 February 2015 22:42, Kevin Wright wrote:

> I think it would be nice for Rmd buffers to have an electric-backtick
> function that auto-inserts the chunk delimiters for R chunks, similar
> to the way that Rnw files can auto-insert the R chunk delimiters <<>>=
>   @.
>
> In the meantime, I hard-coded ctrl-backtick to insert the delimiters,
> wrapping the delimiters around the current region if it is active.
>
> I don't really grok lisp, so this code is horrible, but it more or less works.
>
> Improvements would be welcome.
>
> Kevin
>
>
> (global-set-key (kbd "C-`") 'ess-insert-rmd-chunk)
>
> ; Some code derived from wrap-region
> ; https://github.com/rejeep/wrap-region.el/blob/master/wrap-region.el
> (defun ess-insert-rmd-chunk (arg)
>     "Insert R chunk delimiters"
>   (interactive "*P")
>   ;; no region, and blank line
>   (if (and (not (region-active-p))
>            (looking-at "[ \t]*$"))
>       (let ((pos (point)))
>             (save-excursion
>               (insert "```{r}\n\n```")
>               (goto-char (+ pos 3) ) ) ) ) ; does NOT move forward.  Why?
>   ;; region active
>   (if (region-active-p)
>
>       (let ((beg (region-beginning))
>             (end (region-end))
>             (pos (point)))
>         (save-excursion
>           (goto-char end)
>           (forward-line) ; region-end seems to be at start of previous line ???
>           (insert "```\n")
>           (goto-char beg)
>           (insert "```{r}\n") ) ) ) )