Emacs Alt key with Unicode xterm

(unless (display-graphic-p)
  ;; deal with the Unicode sequences that xterm sends when Alt (meta) keys
  ;; are used. N.B. Works with Alt-letter, Alt-\, Alt-space, and Alt-Shift-:
  (defun make-meta-key ()
    (interactive)
    (let ((e (read-event)))
      ;; (message "Got event %s; basic event is %s" e (event-basic-type e))
      (if (numberp e)
          (let* ((basic (event-basic-type e))
                 (shifted (+ basic 64))
                 (basecode (if (<= shifted 127) shifted basic))
                 (keys (vector (event-convert-list (list 'meta basecode))))
                 (command (key-binding keys)))
              ;; (message "Result is %s; commandp says %s" command (commandp command))
              (command-execute command))
        (error "this can't happen"))))
  (global-set-key [?\M-C] 'make-meta-key)
  (defun do-nothing () (interactive) nil)
  (global-set-key [?\M-B] 'do-nothing))