[PATCH 1/2] Add new function derived-mode-parents

[PATCH 1/2] Add new function derived-mode-parents

[Julien Danjou]

Signed-off-by: Julien Danjou <julien@danjou.info>
---
 lisp/ChangeLog             |    4 ++++
 lisp/emacs-lisp/derived.el |    7 +++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c3b8d52..3ea0487 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,7 @@
+2011-02-08  Julien Danjou  <julien@danjou.info>
+
+	* emacs-lisp/derived.el (derived-mode-parents): New function.
+
 2011-02-07  Jay Belanger  <jay.p.belanger@gmail.com>
 
 	* calc/calc-units.el (math-logunits-quant): Add support for
diff --git a/lisp/emacs-lisp/derived.el b/lisp/emacs-lisp/derived.el
index 425a77e..5adba0e 100644
--- a/lisp/emacs-lisp/derived.el
+++ b/lisp/emacs-lisp/derived.el
@@ -277,6 +277,13 @@ is not very useful."
   mode)
 (make-obsolete 'derived-mode-class 'derived-mode-p "22.1")
 
+(defun derived-mode-parents (mode)
+  "Return the list of ancestors for MODE.
+MODE is included in the result."
+  (loop with mode = major-mode
+        while mode
+        collect mode
+        do (setq mode (get mode 'derived-mode-parent))))
 \f
 ;;; PRIVATE
 
-- 
1.7.2.3

[PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Julien Danjou]

This allows to add font-lock keyword to prog-mode directly, so every other
children mode will use them.

Signed-off-by: Julien Danjou <julien@danjou.info>
---
 lisp/ChangeLog    |    5 +++++
 lisp/font-lock.el |   15 ++++++++++++---
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 3ea0487..d405f47 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,10 @@
 2011-02-08  Julien Danjou  <julien@danjou.info>
 
+	* font-lock.el (font-lock-assq-mode): New function: execute assq
+	for a mode and its parents.
+	(font-lock-value-in-major-mode): Use font-lock-assq-mode.
+	(font-lock-set-defaults): Use font-lock-assq-mode.
+
 	* emacs-lisp/derived.el (derived-mode-parents): New function.
 
 2011-02-07  Jay Belanger  <jay.p.belanger@gmail.com>
diff --git a/lisp/font-lock.el b/lisp/font-lock.el
index b7b617f..9996424 100644
--- a/lisp/font-lock.el
+++ b/lisp/font-lock.el
@@ -1732,11 +1732,18 @@ If SYNTACTIC-KEYWORDS is non-nil, it means these keywords are used for
 				 (funcall keywords)
 			       (eval keywords)))))
 
+(defun font-lock-assq-mode (mode alist)
+  "Call `assq' with MODE and its parents on ALIST."
+  (loop for m in (derived-mode-parents mode)
+        for v = (assq m alist)
+        if v return v))
+
 (defun font-lock-value-in-major-mode (alist)
   "Return value in ALIST for `major-mode', or ALIST if it is not an alist.
 Structure is ((MAJOR-MODE . VALUE) ...) where MAJOR-MODE may be t."
   (if (consp alist)
-      (cdr (or (assq major-mode alist) (assq t alist)))
+      (cdr (or (font-lock-assq-mode major-mode alist)
+               (assq t alist)))
     alist))
 
 (defun font-lock-choose-keywords (keywords level)
@@ -1789,9 +1796,11 @@ Sets various variables using `font-lock-defaults' and
 	   (keywords
 	    (font-lock-choose-keywords (nth 0 defaults)
 				       (font-lock-value-in-major-mode font-lock-maximum-decoration)))
-	   (local (cdr (assq major-mode font-lock-keywords-alist)))
+	   (local (cdr (font-lock-assq-mode
+                        major-mode font-lock-keywords-alist)))
 	   (removed-keywords
-	    (cdr-safe (assq major-mode font-lock-removed-keywords-alist))))
+	    (cdr-safe (font-lock-assq-mode
+                       major-mode font-lock-removed-keywords-alist))))
       (set (make-local-variable 'font-lock-defaults) defaults)
       ;; Syntactic fontification?
       (if (nth 1 defaults)
-- 
1.7.2.3

Re: [PATCH 1/2] Add new function derived-mode-parents

[Stefan Monnier]

> +	* emacs-lisp/derived.el (derived-mode-parents): New function.

What for?


        Stefan

Re: [PATCH 1/2] Add new function derived-mode-parents

[Julien Danjou]

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On Tue, Feb 08 2011, Stefan Monnier wrote:

>> +	* emacs-lisp/derived.el (derived-mode-parents): New function.
>
> What for?

For the second patch. :)

-- 
Julien Danjou
❱ http://julien.danjou.info

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Re: [PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Stefan Monnier]

> This allows to add font-lock keyword to prog-mode directly, so every other
> children mode will use them.

Making inheritance work with font-lock keywords is a good idea, but this
is the wrong way to do it.  The right way is to take advantage of the
way inheritance works.  E.g. use a variable which modes would
*modify* rather than just set.  E.g. somehow convince all modes to use
the equivalent of font-lock-add-keywords.


        Stefan

Re: [PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Julien Danjou]

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On Wed, Feb 09 2011, Stefan Monnier wrote:

>> This allows to add font-lock keyword to prog-mode directly, so every other
>> children mode will use them.
>
> Making inheritance work with font-lock keywords is a good idea, but this
> is the wrong way to do it.  The right way is to take advantage of the
> way inheritance works.  E.g. use a variable which modes would
> *modify* rather than just set.  E.g. somehow convince all modes to use
> the equivalent of font-lock-add-keywords.

I may not have enough knowledge of modes and font-lock to understand the
way you describe. Would you mind ellaboring a bit so I can maybe work on
that? :)

-- 
Julien Danjou
❱ http://julien.danjou.info

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Re: [PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Stefan Monnier]

>>> This allows to add font-lock keyword to prog-mode directly, so every other
>>> children mode will use them.
>> 
>> Making inheritance work with font-lock keywords is a good idea, but this
>> is the wrong way to do it.  The right way is to take advantage of the
>> way inheritance works.  E.g. use a variable which modes would
>> *modify* rather than just set.  E.g. somehow convince all modes to use
>> the equivalent of font-lock-add-keywords.

> I may not have enough knowledge of modes and font-lock to understand the
> way you describe. Would you mind ellaboring a bit so I can maybe work on
> that? :)

If modes *add* keywords to `font-lock-new-keywords', then children of
prog-mode will automatically inherit the prog-mode's keyword since
variables set by the parent are carried to the child.

So, I think we should change font-lock.el so that major modes setup
font-lock keywords by adding them to a variable.  For backward
compatibility, the keywords listed in font-lock-defaults would be added,
of course.


        Stefan

Re: [PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Julien Danjou]

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On Wed, Feb 09 2011, Stefan Monnier wrote:

> If modes *add* keywords to `font-lock-new-keywords', then children of
> prog-mode will automatically inherit the prog-mode's keyword since
> variables set by the parent are carried to the child.
>
> So, I think we should change font-lock.el so that major modes setup
> font-lock keywords by adding them to a variable.  For backward
> compatibility, the keywords listed in font-lock-defaults would be added,
> of course.

Just to be clean, what I was trying to fix actually is something I do in
my configuration file:

#+begin_src: emacs-lisp
(font-lock-add-keywords
 'prog-mode   
 '(("\\<\\(FIXME\\|HACK\\|XXX\\|TODO\\)" 1 font-lock-warning-face prepend)))
#+end_src

This is not something modes do, I think. But doing that have no effect,
because font-lock does not check inheritance, therefore my patches.

-- 
Julien Danjou
❱ http://julien.danjou.info

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Re: [PATCH 2/2] Make font-lock honor parents mode of current major-mode

[Stefan Monnier]

> #+begin_src: emacs-lisp
> (font-lock-add-keywords
>  'prog-mode   
>  '(("\\<\\(FIXME\\|HACK\\|XXX\\|TODO\\)" 1 font-lock-warning-face prepend)))
> #+end_src

> This is not something modes do, I think. But doing that have no effect,
> because font-lock does not check inheritance, therefore my patches.

The `prog-mode' argument to font-lock-add-keywords is the reason why
you'd need to explicitly check inheritance.
If you use

  (add-hook 'prog-mode-hook
            (lambda ()
              (font-lock-add-keywords
               nil
               '(("\\<\\(FIXME\\|HACK\\|XXX\\|TODO\\)"
                  1 font-lock-warning-face prepend)))))

then things can be made to work without ever having to look at the
inheritance data.  But of course, the above won't work either with the
current font-lock.el.  That's what we need to fix.


        Stefan