text modes vs. programming language modes

[Kevin Rodgers]

Is there a reliable way to determine whether the current major mode
is a text mode vs. a programming language mode?  For example, do all
text modes use a keymap that inherits from text-mode-map or a syntax
table that inherits from text-mode-syntax-table?

I suspect not, so I'm thinking of using something like:

(defun major-mode-type ()
  (let ((lisp-directory (expand-file-name "../lisp" data-directory))
        (mode-directory (directory-file-name
                         (file-name-directory
                          (symbol-file major-mode 'defun)))))
    (and (not (equal lisp-directory mode-directory))
         (file-relative-name mode-directory lisp-directory))))

which e.g. returns nil for dired-mode and Info-mode, "textmodes" for 
text-mode and sgml-mode,  and "progmodes" for java-mode and sql-mode.

--
Kevin