(require 'cl-lib)
; clean-mode-line from http://www.masteringemacs.org/articles/2012/09/10/hiding-replacing-modeline-strings/
(require 'cl)
(defvar mode-line-cleaner-alist
  `((auto-complete-mode . " α")
    (yas/minor-mode . " υ")
    (paredit-mode . " π")
    (eldoc-mode . "")
    (abbrev-mode . "")
    (my-keys-minor-mode . "")
    (helm-mode . "☸")
    ;; Major modes
    (lisp-interaction-mode . "λ")
    (hi-lock-mode . "")
    (python-mode . "Py")
    (cperl-mode . "ρ")
    (auctex-mode . "Lχ")
    (org-agenda-mode . "øα")
    (org-mode . "ø")
    (emacs-lisp-mode . "EL")
    (nxhtml-mode . "nx"))
  "Alist for `clean-mode-line'.
 
When you add a new element to the alist, keep in mind that you
must pass the correct minor/major mode symbol and a string you
want to use in the modeline *in lieu of* the original.")
 
 
(defun clean-mode-line ()
  (interactive)
  (cl-loop for cleaner in mode-line-cleaner-alist
        do (let* ((mode (car cleaner))
                 (mode-str (cdr cleaner))
                 (old-mode-str (cdr (assq mode minor-mode-alist))))
             (when old-mode-str
                 (setcar old-mode-str mode-str))
               ;; major mode
             (when (eq mode major-mode)
               (setq mode-name mode-str)))))
 
 
(add-hook 'after-change-major-mode-hook 'clean-mode-line)