问spacemacs ess knitr不适用于Rmd文件

EN

dotspacemacs-configuration-layers
 '(
   html

 ;; ----------------------------------------------------------------
 ;; Example of useful layers you may want to use right away.
 ;; Uncomment some layer names and press <SPC f e R> (Vim style) or
 ;; <M-m f e R> (Emacs style) to install them.
 ;; ----------------------------------------------------------------
 markdown
 helm
 ess
 auto-completion
 better-defaults
 emacs-lisp
 git
 polymode
 mu4e
 ;; markdown
 ;; (shell :variables
 org 
 ;;        shell-default-height 30
 ;;        shell-default-position 'bottom)
 spell-checking
 syntax-checking
 ;; version-control
 )

;;; packages.el --- polymode layer packages file for Spacemacs.
;;
;; Copyright (c) 2012-2016 Sylvain Benner & Contributors
;;
;; Author: Walmes Zeviani & Fernando Mayer
;; URL: https://github.com/syl20bnr/spacemacs

;;; Code:

(defconst polymode-packages
 '(polymode))

(defun polymode/init-polymode () 
  (use-package polymode
    :mode (("\\.Rmd"   . Rmd-mode))
    :init
    (progn
      (defun Rmd-mode ()
    "ESS Markdown mode for Rmd files"
    (interactive)
    (require 'poly-R)
    (require 'poly-markdown)
    (R-mode)
    (poly-markdown+r-mode))
  ))
  )

;;; packages.el ends here