In Common Lisp:

    (setf h (make-hash-table))
    (setf (gethash 'foo h) "hi") ;; -> "hi"
    (gethash 'foo h) ;; -> "hi"
    (gethash 'bar h "bye") ;; -> "bye"

That's not too bad. Not quite as perfect as bracket-based dereferencing, but I can live with it.