Re: Recent attempts at standardizing major mode definitions.

[Luc Teirlinck]

Stefan Monnier wrote:

   If there is a difference, it's a bug, so please report it.

Sorry, I should have thought about that possibility.  I assumed the
difference was deliberate.  I include a transcript of an ielm session.
First we define my-mode as a derived mode of text-mode, then as a
derived mode of fundamental-mode.  text-mode's abbrev table gets
copied, fundamental-mode's not.  I believe that whatever behavior for
abbrevs we decide on, the behavior should be the same for both, if we
are talking about a "true" derived mode of fundamental-mode.

===File ~/derivedstuff======================================
*** Welcome to IELM ***  Type (describe-mode) for help.
ELISP> (emacs-version)
"GNU Emacs 21.3.50.1 (i686-pc-linux-gnu, X toolkit)\n of 2002-09-01 on 
swt40.swt.com"
ELISP> (macroexpand `(define-derived-mode my-mode text-mode "Mymode" 
"docstring" (defvar mymode-var 1)))
(progn
  (defvar my-mode-map
    (make-sparse-keymap))
  (defvar my-mode-syntax-table
    (make-syntax-table))
  (defvar my-mode-abbrev-table
    (progn
      (define-abbrev-table 'my-mode-abbrev-table nil)
      my-mode-abbrev-table))
  (put 'my-mode 'derived-mode-parent 'text-mode)
  (defun my-mode nil "docstring\n\nIn addition to any hooks its parent mode 
`text-mode' might have run,\nthis mode runs the hook `my-mode-hook', as the 
final step\nduring initialization.\n\n\\{my-mode-map}"
    (interactive)
    (delay-mode-hooks
     (text-mode)
     (setq major-mode 'my-mode)
     (setq mode-name "Mymode")
     (progn
       (if
           (get 'text-mode 'mode-class)
           (put 'my-mode 'mode-class
                (get 'text-mode 'mode-class)))
       (unless
           (keymap-parent my-mode-map)
         (set-keymap-parent my-mode-map
                            (current-local-map)))
       (let
           ((parent
             (char-table-parent my-mode-syntax-table)))
         (unless
             (and parent
                  (not
                   (eq parent
                       (standard-syntax-table))))
           (set-char-table-parent my-mode-syntax-table
                                  (syntax-table))))
       (when local-abbrev-table
         (mapatoms
          (lambda
            (symbol)
            (or
             (intern-soft
              (symbol-name symbol)
              my-mode-abbrev-table)
             (define-abbrev my-mode-abbrev-table
               (symbol-name symbol)
               (symbol-value symbol)
               (symbol-function symbol))))
          local-abbrev-table)))
     (use-local-map my-mode-map)
     (set-syntax-table my-mode-syntax-table)
     (setq local-abbrev-table my-mode-abbrev-table)
     (defvar mymode-var 1))
    (run-mode-hooks 'my-mode-hook)))

ELISP> (macroexpand `(define-derived-mode my-mode fundamental-mode "Mymode" 
"docstring" (defvar mymode-var 1)))
(progn
  (defvar my-mode-map
    (make-sparse-keymap))
  (defvar my-mode-syntax-table
    (make-syntax-table))
  (defvar my-mode-abbrev-table
    (progn
      (define-abbrev-table 'my-mode-abbrev-table nil)
      my-mode-abbrev-table))
  (put 'my-mode 'derived-mode-parent 'nil)
  (defun my-mode nil "docstring\n\nThis mode runs the hook `my-mode-hook', as 
the final step\nduring initialization.\n\n\\{my-mode-map}"
    (interactive)
    (delay-mode-hooks
     (kill-all-local-variables)
     (setq major-mode 'my-mode)
     (setq mode-name "Mymode")
     nil
     (use-local-map my-mode-map)
     (set-syntax-table my-mode-syntax-table)
     (setq local-abbrev-table my-mode-abbrev-table)
     (defvar mymode-var 1))
    (run-mode-hooks 'my-mode-hook)))

ELISP> 
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