`markdown-mmm-auto-modes` defines pairs of language and mode names

where the mode name is different from the language name

layers/+lang/markdown/README.org

@@ -67,13 +67,14 @@ markdown buffer in Chrome. Please refer to =chrome= layer documentation for more
 information.
 
 ** Automatic MMM-Mode Generation
-To generate MMM-Modes for languages where the language name directly relates to
-the Emacs mode name, set the value of the variable =markdown-mmm-auto-modes= to
-a list of the languages:
+To generate MMM-Modes for languages set the value of the variable
+=markdown-mmm-auto-modes= to a list of the languages. For languages where the
+mode name directly relates to the language name, use a string. Otherwise, use a
+list of `("language" "mode")`:
 
 #+BEGIN_SRC emacs-lisp
   dotspacemacs-configuration-layers '(
-    (markdown :variables markdown-mmm-auto-modes '("c" "c++" "python" "scala"))
+    (markdown :variables markdown-mmm-auto-modes '("c" "c++" "python" "scala" ("elisp" "emacs-lisp"))
 #+END_SRC
 
 * Usage

layers/+lang/markdown/config.el

@@ -15,6 +15,5 @@
   "Possibe values are `eww' (built-in browser) or `vmd' (installed with `npm').")
 
 (defvar markdown-mmm-auto-modes
-  '("c" "c++" "css" "java" "javascript" "python" "ruby" "rust" "scala")
-  "Automatically add mmm class for languages where its name and mode name are
-directly related")
+  '("c" "c++" "css" "java" "javascript" "python" "ruby" "rust" "scala" ("html" "web") ("elisp" "emacs-lisp") ("ess" "R"))
+  "List of language names or lists of language and mode names for which to generate mmm classes.")

layers/+lang/markdown/packages.el

@@ -44,11 +44,13 @@
   (add-hook 'markdown-mode-hook 'smartparens-mode))
 
 ;; from Jason Blevins http://jblevins.org/log/mmm
-(defun markdown/mmm-auto-class (lang &optional submode)
-  (let ((class (intern (concat "markdown-" lang)))
-        (submode (or submode (intern (concat lang "-mode"))))
-        (front (concat "^```" lang "[\n\r]+"))
-        (back "^```$"))
+(defun markdown/mmm-auto-class (lang)
+  (let* ((l (if (listp lang) (car lang) lang))
+         (s (if (listp lang) (cadr lang) lang))
+         (class (intern (concat "markdown-" l)))
+         (submode (intern (concat s "-mode")))
+         (front (concat "^```" l "[\n\r]+"))
+         (back "^```$"))
     (mmm-add-classes (list (list class
                                :submode submode
                                :front front
@@ -182,14 +184,8 @@ Will work on both org-mode and any mode that accepts plain html."
     :init (add-hook 'markdown-mode-hook 'spacemacs/activate-mmm-mode)
     :config
     (progn
-      ;; Automatically add mmm class for languages where its name and mode
-      ;; name are directly related
+      ;; Automatically add mmm class for languages
       (mapc 'markdown/mmm-auto-class markdown-mmm-auto-modes)
-
-      ;; Otherwise define these manually
-      (markdown/mmm-auto-class "html" 'web-mode)
-      (markdown/mmm-auto-class "elisp" 'emacs-lisp-mode)
-      (markdown/mmm-auto-class "ess" 'R-mode)
       (setq mmm-global-mode t))))
 
 (defun markdown/init-vmd-mode ()