show result of evalution to other by adding an arrow

gistfile1.txt

(defun yf/rcirc-eval-last-sexp ()
  "Like `eval-last-sexp', but add an arrow when inserting results
into buffer."
  (interactive)
  (let ((opoint (point))
        (cpa current-prefix-arg))
    (call-interactively 'eval-last-sexp)
    (when cpa
      (save-excursion
        (goto-char opoint)
        (insert " => ")))))
(define-key rcirc-mode-map (kbd "C-x C-e") 'yf/rcirc-eval-last-sexp)