gistfile1.el

(defun esk-pretty-lambdas ()                                                                                                                 │
  (font-lock-add-keywords                                                                                                                    │
   nil `(("(?\\(lambda\\>\\)"                                                                                                                │
          (0 (progn (compose-region (match-beginning 1) (match-end 1)                                                                        │
                                    ,(make-char 'greek-iso8859-7 107))                                                                       │
                    nil))))))
                    
(add-hook 'prog-mode-hook 'esk-pretty-lambdas)