ElDoc: adding optional support to display messages in header-line instead of the echo area

ElDoc: adding optional support to display messages in header-line instead of the echo area

[Geralt]

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Hi,

I've added to ElDoc a customizable flag to redirect the output into
the header-line instead of the echo area. It's my first contribution
and I'm not sure if the patch is implementing the functionality good
enough to make it into Emacs. I'd like to hear your feedback :)

Here's the patch (and as attachement too, because GoogleMail is doing
changes to whitespace):
--- eldoc.el	2009-07-31 18:03:58.000000000 +0200
+++ eldoc.el	2009-08-01 11:43:29.587798820 +0200
@@ -105,6 +105,12 @@
  enable argument list to fit on one line" truncate-sym-name-if-fit))
   :group 'eldoc)

+(defcustom eldoc-display-in-header-line nil
+  "If set eldoc will display its messages in the topmost line of the
window, called the header-line, instead of the echo area.
+Use only when eldoc-echo-area-use-multiline-p is set to nil."
+  :type 'boolean
+  :group 'eldoc)
+
 (defface eldoc-highlight-function-argument
   '((t (:inherit bold)))
   "Face used for the argument at point in a function's argument list.
@@ -201,8 +207,10 @@
     ;; they are Legion.
     ;; Emacs way of preventing log messages.
     (let ((message-log-max nil))
-      (cond (eldoc-last-message (message "%s" eldoc-last-message))
-	    (omessage (message nil)))))
+      (cond (eldoc-last-message (if eldoc-display-in-header-line
+				    (setq header-line-format eldoc-last-message)
+				  (message "%s" eldoc-last-message)
+				  (omessage (message nil)))))))
   eldoc-last-message)

 ;; This function goes on pre-command-hook for XEmacs or when using idle




Geralt.

[-- Attachment #2: eldoc-display-in-header-line.patch --]
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--- eldoc.el	2009-07-31 18:03:58.000000000 +0200
+++ eldoc.el	2009-08-01 11:43:29.587798820 +0200
@@ -105,6 +105,12 @@
  enable argument list to fit on one line" truncate-sym-name-if-fit))
   :group 'eldoc)
 
+(defcustom eldoc-display-in-header-line nil
+  "If set eldoc will display its messages in the topmost line of the window, called the header-line, instead of the echo area.
+Use only when eldoc-echo-area-use-multiline-p is set to nil."
+  :type 'boolean
+  :group 'eldoc)
+
 (defface eldoc-highlight-function-argument
   '((t (:inherit bold)))
   "Face used for the argument at point in a function's argument list.
@@ -201,8 +207,10 @@
     ;; they are Legion.
     ;; Emacs way of preventing log messages.
     (let ((message-log-max nil))
-      (cond (eldoc-last-message (message "%s" eldoc-last-message))
-	    (omessage (message nil)))))
+      (cond (eldoc-last-message (if eldoc-display-in-header-line
+				    (setq header-line-format eldoc-last-message)
+				  (message "%s" eldoc-last-message)
+				  (omessage (message nil)))))))
   eldoc-last-message)
 
 ;; This function goes on pre-command-hook for XEmacs or when using idle

Re: ElDoc: adding optional support to display messages in header-line instead of the echo area

[martin rudalics]

 > +      (cond (eldoc-last-message (if eldoc-display-in-header-line
 > +				    (setq header-line-format eldoc-last-message)
 > +				  (message "%s" eldoc-last-message)
 > +				  (omessage (message nil)))))))

You probably mean something like

       (cond
        (eldoc-last-message
	(if eldoc-display-in-header-line
	    (setq header-line-format eldoc-last-message)
	  (message "%s" eldoc-last-message)))
        (omessage (message nil)))))

here ;-)

martin

Re: ElDoc: adding optional support to display messages in header-line instead of the echo area

[Geralt]

On Sun, Aug 2, 2009 at 11:33 AM, martin rudalics<rudalics@gmx.at> wrote:
>> +      (cond (eldoc-last-message (if eldoc-display-in-header-line
>> +                                 (setq header-line-format
>> eldoc-last-message)
>> +                               (message "%s" eldoc-last-message)
>> +                               (omessage (message nil)))))))
>
> You probably mean something like
>
>      (cond
>       (eldoc-last-message
>        (if eldoc-display-in-header-line
>            (setq header-line-format eldoc-last-message)
>          (message "%s" eldoc-last-message)))
>       (omessage (message nil)))))
>
> here ;-)
>
> martin
>
Hi Martin,

can you explain why? I put the omessage into the ELSE block because
somebody on emacs-help suggested it and it made sense to me at that
time.



Geralt.

Re: ElDoc: adding optional support to display messages in header-line instead of the echo area

[Tassilo Horn]

Geralt <usr.gentoo@googlemail.com> writes:

Hi!

>> You probably mean something like
>>
>>      (cond
>>       (eldoc-last-message
>>        (if eldoc-display-in-header-line
>>            (setq header-line-format eldoc-last-message)
>>          (message "%s" eldoc-last-message)))
>>       (omessage (message nil)))))
>>
>> here ;-)
>
> can you explain why?

Cause the variable `omessage' is bound to `eldoc-last-message' in the
beginning of the function, and it serves as condition in the `cond'.
After the `let', `eldoc-last-message' set to the new eldoc string.  If
there's non created, cause point is not on a function/var, then the new
value is nil.  If that is the case, but the old message (omessage) is
non-nil, the echo area will be cleared.

> I put the omessage into the ELSE block because somebody on emacs-help
> suggested it and it made sense to me at that time.

Yep, been there, didn't check accurately, didn't object.  But Martin is
right. :-)

Bye,
Tassilo

Re: ElDoc: adding optional support to display messages in header-line instead of the echo area

[martin rudalics]

 > can you explain why? I put the omessage into the ELSE block because
 > somebody on emacs-help suggested it and it made sense to me at that
 > time.

Compiling eldoc.el after applying your patch gets me

eldoc-new.el~:550:1:Warning: the function `omessage' is not known to be
     defined.

This happens because in the

       (cond (eldoc-last-message (if eldoc-display-in-header-line
				    (setq header-line-format eldoc-last-message)
				  (message "%s" eldoc-last-message)
				  (omessage (message nil)))))))

form you misplaced the parentheses and thus `omessage' is not considered
a condition of some clause of the `cond' special form but as a function
call.

BTW, I suppose you also need to call `force-mode-line-update' because
Emacs does not necessarily update the contents of the header line when
just moving point.

martin

Re: ElDoc: adding optional support to display messages in header-line

[Stefan Monnier]

> +		    (setq header-line-format eldoc-last-message)

If eldoc-last-message contains % characters, this can lead to surprising
results, because they get special treatment.  Better set
header-line-format to '("" eldoc-message) in eldoc-mode and then set
eldoc-message here.


        Stefan

Re: ElDoc: adding optional support to display messages in header-line

[Stefan Monnier]

> I've added to ElDoc a customizable flag to redirect the output into
> the header-line instead of the echo area. It's my first contribution
> and I'm not sure if the patch is implementing the functionality good
> enough to make it into Emacs. I'd like to hear your feedback :)

BTW, I'm not sure it's a good feature.  Also, the docstring of
eldoc-display-in-header-line needs to start with a line that stands on
its own.


        Stefan

Re: ElDoc: adding optional support to display messages in header-line instead of the echo area

[Geralt]

On Tue, Aug 4, 2009 at 10:32 AM, martin rudalics<rudalics@gmx.at> wrote:
>> can you explain why? I put the omessage into the ELSE block because
>> somebody on emacs-help suggested it and it made sense to me at that
>> time.
>
> Compiling eldoc.el after applying your patch gets me
>
> eldoc-new.el~:550:1:Warning: the function `omessage' is not known to be
>    defined.
>
> This happens because in the
>
>      (cond (eldoc-last-message (if eldoc-display-in-header-line
>                                    (setq header-line-format
> eldoc-last-message)
>                                  (message "%s" eldoc-last-message)
>                                  (omessage (message nil)))))))
>
> form you misplaced the parentheses and thus `omessage' is not considered
> a condition of some clause of the `cond' special form but as a function
> call.
>
> BTW, I suppose you also need to call `force-mode-line-update' because
> Emacs does not necessarily update the contents of the header line when
> just moving point.
>
> martin
>

Ok, I did all the changes, here's the patch with all the changes:

--- eldoc.el	2009-08-04 20:48:20.789335848 +0200
+++ eldoc.el	2009-08-04 20:47:34.350337476 +0200
@@ -105,6 +105,11 @@
  enable argument list to fit on one line" truncate-sym-name-if-fit))
   :group 'eldoc)

+(defcustom eldoc-display-in-header-line nil
+  "If set eldoc will display its messages in the topmost line of the
window, called the header-line, instead of the echo area."
+  :type 'boolean
+  :group 'eldoc)
+
 (defface eldoc-highlight-function-argument
   '((t (:inherit bold)))
   "Face used for the argument at point in a function's argument list.
@@ -201,7 +206,11 @@
     ;; they are Legion.
     ;; Emacs way of preventing log messages.
     (let ((message-log-max nil))
-      (cond (eldoc-last-message (message "%s" eldoc-last-message))
+      (cond (eldoc-last-message (if eldoc-display-in-header-line
+				    (progn
+				      (setq header-line-format eldoc-last-message)
+				      (force-mode-line-update))
+				  (message "%s" eldoc-last-message)))
 	    (omessage (message nil)))))
   eldoc-last-message)



Geralt.

Re: ElDoc: adding optional support to display messages in header-line

[Geralt]

On Tue, Aug 4, 2009 at 7:05 PM, Stefan Monnier<monnier@iro.umontreal.ca> wrote:
>> +                 (setq header-line-format eldoc-last-message)
>
> If eldoc-last-message contains % characters, this can lead to surprising
> results, because they get special treatment.  Better set
> header-line-format to '("" eldoc-message) in eldoc-mode and then set
> eldoc-message here.
>
>
>        Stefan
>
>
I tried that, but then the output in the header line is no longer
using the syntax colors of the current mode. Is there a way to get
both?



Geralt.

Re: ElDoc: adding optional support to display messages in header-line

[Geralt]

On Tue, Aug 4, 2009 at 7:07 PM, Stefan Monnier<monnier@iro.umontreal.ca> wrote:
>> I've added to ElDoc a customizable flag to redirect the output into
>> the header-line instead of the echo area. It's my first contribution
>> and I'm not sure if the patch is implementing the functionality good
>> enough to make it into Emacs. I'd like to hear your feedback :)
>
> BTW, I'm not sure it's a good feature.  Also, the docstring of
> eldoc-display-in-header-line needs to start with a line that stands on
> its own.
>
>
>        Stefan
>
Ok, thanks, I'll change the docstring.



Geralt.

Re: ElDoc: adding optional support to display messages in header-line

[Stefan Monnier]

> I tried that, but then the output in the header line is no longer
> using the syntax colors of the current mode. Is there a way to get
> both?

Yesm you need to (put 'eldoc-messagee 'risky-local-variable t)


        Stefa

Re: ElDoc: adding optional support to display messages in header-line

[Geralt]

On Wed, Aug 5, 2009 at 4:00 AM, Stefan Monnier<monnier@iro.umontreal.ca> wrote:
>> I tried that, but then the output in the header line is no longer
>> using the syntax colors of the current mode. Is there a way to get
>> both?
>
> Yesm you need to (put 'eldoc-messagee 'risky-local-variable t)
>
>
>        Stefa
>
Thanks. Where can I get information about properties (like this one)?
I couldn't find anything with C-a or searching through the emacs info
page(s).




Geralt.