Emacs で `|>` を楽に入力する ref: http://qiita.com/__hage/items/a8a99b996fd266ccbcf5

init.el

(eval-after-load "elixir-mode"
  #'(progn
      ;; 改行して行頭に |> をつける
      (defun my-elixir-newline-and-insert-pipe ()
        (interactive)
        (move-end-of-line 1)
        (newline-and-indent)
        (insert "|> "))
      (define-key elixir-mode-map (kbd "M-J") 'my-elixir-newline-and-insert-pipe)))