modified-md.el

  (with-eval-after-load 'org
    (progn
      (setq org-src-lang-modes
            (-cons* '("tut" . scala)
                    '("tut:silent" . scala)
                    '("tut:book" . scala)
                    org-src-lang-modes))
      ;;(advice-add 'org-md-link :override
      (defun org-modified-md-link (link contents info)
        (let ((link-org-files-as-md (lambda (raw-path)
          ;; Treat links to `file.org' as links to `file.md'.
          (if (string= ".org" (downcase (file-name-extension raw-path ".")))
              (concat (file-name-sans-extension raw-path) ".md")
            raw-path)))
        (type (org-element-property :type link)))
          (message "In modified func")
          (cond
          ;; Link type is handled by a special function.
          ((org-export-custom-protocol-maybe link contents 'md))
          ((member type '("custom-id" "id" "fuzzy"))
            (let ((destination (if (string= type "fuzzy")
                (org-export-resolve-fuzzy-link link info)
              (org-export-resolve-id-link link info))))
        (pcase (org-element-type destination)
          (`plain-text			; External file.
          (let ((path (funcall link-org-files-as-md destination)))
            (if (not contents) (format "<%s>" path)
              (format "[%s](%s)" contents path))))
          (`headline
          (format
            "[%s](#%s)"
            ;; Description.
            (cond ((org-string-nw-p contents))
            ((org-export-numbered-headline-p destination info)
            (mapconcat #'number-to-string
                  (org-export-get-headline-number destination info)
                  "."))
            (t (org-export-data (org-element-property :title destination)
                    info)))
            ;; Reference.
            (or (org-element-property :CUSTOM_ID destination)
          (org-export-get-reference destination info))))
          (_
          (let ((description
            (or (org-string-nw-p contents)
                (let ((number (org-export-get-ordinal destination info)))
            (cond
            ((not number) nil)
            ((atom number) (number-to-string number))
            (t (mapconcat #'number-to-string number ".")))))))
            (when description
              (format "[%s](#%s)"
                description
                (org-export-get-reference destination info))))))))
          ((org-export-inline-image-p link org-html-inline-image-rules)
            (let ((path (let ((raw-path (org-element-property :path link)))
              (cond ((not (equal "file" type)) (concat type ":" raw-path))
              ((not (file-name-absolute-p raw-path)) raw-path)
              (t (expand-file-name raw-path)))))
            (caption (org-export-data
                (org-export-get-caption
                (org-export-get-parent-element link)) info)))
            (format "![%s](%s)"
              (if (org-string-nw-p caption) caption "img")
              path)))
          ((string= type "coderef")
            (let ((ref (org-element-property :path link)))
        (format (org-export-get-coderef-format ref contents)
          (org-export-resolve-coderef ref info))))
          ((equal type "radio") contents)
          (t (let* ((raw-path (org-element-property :path link))
              (path
          (cond
          ((member type '("http" "https" "ftp" "mailto"))
            (concat type ":" raw-path))
          ((string= type "file")
            (org-export-file-uri (funcall link-org-files-as-md raw-path)))
          (t raw-path))))
          (if (not contents) (format "<%s>" path)
            (format "[%s](%s)" contents path)))))))
      (defun org-export-to-modified-gfm (&optional async subtreep visible-only)
        (interactive)
        (let ((outfile (org-export-output-file-name ".md" subtreep)))
          (org-export-to-file 'modified-gfm outfile async subtreep visible-only)))
      (defun org-export-as-modified-gfm (&optional async subtreep visible-only)
        (interactive)
        (org-export-to-buffer 'modified-gfm "*Org GFM Export*"
          async subtreep visible-only nil nil (lambda () (text-mode))))
      (org-export-define-derived-backend 'modified-gfm 'gfm
        :filters-alist '((:filter-parse-tree . org-md-separate-elements))
        :menu-entry
        '(?i "Export to Modified Markdown"
            ((?I "To temporary buffer"
            (lambda (a s v b) (org-export-as-modified-gfm a s v)))
        (?i "To file" (lambda (a s v b) (org-export-to-modified-gfm a s v)))
        (?o "To file and open"
            (lambda (a s v b)
              (if a (org-export-to-modified-gfm t s v)
                (org-open-file (org-export-to-modified-gfm nil s v)))))))
        :translate-alist '((link . org-modified-md-link)))))