Key binding for pipe in ESS

Question

I am trying to define keymapping about %>% for ess R mode.
Code 1 is my init.el based on How to implement the piping operator %>% in ESS mode?. After evaluation of the code, I get the key binding Code 2. I don't know why such a situation happen and RET does not work well. How do I fix it?

Code 1

(defun then_R_operator ()
  (interactive)
  (just-one-space 1)
  (insert "%>%"))

(define-key ess-mode-map (kbd "C-%") 'then_R_operator)
(define-key inferior-ess-mode-map (kbd "C-%") 'then_R_operator)

Code 2

key             binding
---             -------
RET     then_R_operator
C-%     then_R_operator

Update

I also try a different method as follows. But, I got the same result.

(define-key ess-mode-map (kbd "C-M") "%>%")
(define-key inferior-ess-mode-map (kbd "C-M") "%>%")

Answer 1

I found an easy solution from https://stackoverflow.com/questions/59251402/how-to-set-up-custom-automatic-character-replacement-in-emacs-ess.

(define-key ess-mode-map (kbd "C-%") "%>%")
(define-key inferior-ess-mode-map (kbd "C-%") "%>%")

Note C-M causes a problem.

Answer 2

Another way to define the key binding is with use-package:

(use-package ess
  :bind (:map ess-r-mode-map
         ("C-c >" . " %>% ")
         :map inferior-ess-r-mode-map
         ("C-c >" . " %>% ")))