How to get Org-mode Babel src code block language value?

Question

I set org-mode Babel to open rhtml block with web-mode.

(add-to-list 'org-src-lang-modes '("rhtml" . web))

And I have configure company-robe for completing for Rails code in erb engine.

(defadvice company-robe (before web-mode-set-up-ac-sources activate)
    "Set `robe-mode' based on current language before running `company-robe'."
    (if (equal major-mode 'web-mode)
        (let ((web-mode-cur-language (web-mode-language-at-pos)))
          (if (string= web-mode-cur-language "erb")
              (unless robe-mode (robe-mode))
            (if robe-mode (robe-mode -1))
            ))))

The upper advice work correctly in normal file index.html.erb file.

But web-mode can't recognize engine correctly in Org-mode babel block. When I run (web-mode-language-at-pos), it shows html.

The author of web-mode suggest me to use web-mode-set-engine.

(web-mode-set-engine "erb")

Here the original question I asked in web-mode issues: https://github.com/fxbois/web-mode/issues/678

My problem is the org edited src buffer's major-mode is web-mode, but I want to set web-mode-engine to erb. The only identity in src block is this:

#+BEGIN_SRC rhtml

#+END_SRC

I checked out Org-mode source code, found some functions relative with this.

• org-src-construct-edit-buffer-name (org-buffer-name lang)
• org-babel-expand-src-block
  • org-babel-get-src-block-info (it should return a list: (language body header-arguments-alist switches name indent block-head) )

I tried to run (nth 0 (org-babel-get-src-block-info)) in opened src buffer which is opened by [C-c ']. But only get nil.

Answer 1

I found the solution, add an advice to get lang before [C-c '] keybinding.

;; let Org-mode Babel src code block auto set `web-mode-engine' for rhtml.
  (defadvice org-edit-special (before org-edit-src-code activate)
    (let ((lang (nth 0 (org-babel-get-src-block-info))))
      (if (string= lang "rhtml")
          (web-mode-set-engine "erb"))
      ))