[Old patch] Unify fn and var help to make learning elisp a little easier

[Old patch] Unify fn and var help to make learning elisp a little easier

[Kelly Dean]

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I originally proposed this a couple years ago:
https://lists.gnu.org/archive/html/emacs-devel/2012-12/msg00165.html

At the time, my patch was declined due to a paperwork issue. However, the FSF now has a disclaimer on file for me, so that issue has been solved.

I've been using this patch since the time I wrote it, and find it handy. I rarely use «C-h v» or «C-h f» anymore.

If other people might find it useful too, I propose installing it in Emacs. Stefan and Drew suggested maybe using a different keybinding than «C-h o», though. (I'll have to re-train my muscle memory, but that's ok.) The remaining lowercase options for «C-h» are [juxyz]. Of those, I would vote for x.

A copy of my original patch is attached below.


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--- emacs-24.2/lisp/help-fns.el
+++ emacs-24.2/lisp/help-fns.el
@@ -897,6 +897,37 @@
 
 
 ;;;###autoload
+(defun describe-function-or-variable (symbol &optional buffer frame)
+  "Display the full documentation of the function or variable SYMBOL.
+If SYMBOL is a variable and has a buffer-local value in BUFFER or FRAME
+\(default to the current buffer and current frame), it is displayed along
+with the global value."
+  (interactive
+   (let* ((v-or-f (variable-at-point))
+	 (found (symbolp v-or-f))
+	 (v-or-f (if found v-or-f (function-called-at-point)))
+	 (found (or found v-or-f))
+	 (enable-recursive-minibuffers t)
+	 val)
+     (setq val (completing-read (if found
+				    (format
+				     "Describe function or variable (default %s): " v-or-f)
+				  "Describe function or variable: ")
+				obarray
+				(lambda (vv)
+				  (or (fboundp vv)
+				      (get vv 'variable-documentation)
+				      (and (boundp vv) (not (keywordp vv)))))
+				t nil nil
+				(if found (symbol-name v-or-f))))
+     (list (if (equal val "")
+	       v-or-f (intern val)))))
+  (if (not (symbolp symbol)) (message "You didn't specify a function or variable")
+    (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
+    (unless (frame-live-p frame) (setq frame (selected-frame)))
+    (help-xref-interned symbol buffer frame)))
+
+;;;###autoload
 (defun describe-syntax (&optional buffer)
   "Describe the syntax specifications in the syntax table of BUFFER.
 The descriptions are inserted in a help buffer, which is then displayed.
--- emacs-24.2/lisp/help-mode.el
+++ emacs-24.2/lisp/help-mode.el
@@ -627,10 +627,13 @@
 
 \f
 ;; Additional functions for (re-)creating types of help buffers.
-(defun help-xref-interned (symbol)
+
+;;;###autoload
+(defun help-xref-interned (symbol &optional buffer frame)
   "Follow a hyperlink which appeared to be an arbitrary interned SYMBOL.
 Both variable, function and face documentation are extracted into a single
-help buffer."
+help buffer. If SYMBOL is a variable, include buffer-local value for optional
+BUFFER or FRAME."
   (with-current-buffer (help-buffer)
     ;; Push the previous item on the stack before clobbering the output buffer.
     (help-setup-xref nil nil)
@@ -646,7 +649,7 @@
 			  (get symbol 'variable-documentation))
 		  ;; Don't record the current entry in the stack.
 		  (setq help-xref-stack-item nil)
-		  (describe-variable symbol))))
+		  (describe-variable symbol buffer frame))))
       (cond
        (sdoc
 	;; We now have a help buffer on the variable.
--- emacs-24.2/lisp/help.el
+++ emacs-24.2/lisp/help.el
@@ -90,6 +90,7 @@
     (define-key map "k" 'describe-key)
     (define-key map "l" 'view-lossage)
     (define-key map "m" 'describe-mode)
+    (define-key map "o" 'describe-function-or-variable)
     (define-key map "n" 'view-emacs-news)
     (define-key map "p" 'finder-by-keyword)
     (define-key map "P" 'describe-package)
@@ -215,6 +216,7 @@
 m           Display documentation of current minor modes and current major mode,
               including their special commands.
 n           Display news of recent Emacs changes.
+o SYMBOL    Display the given function or variable's documentation and value.
 p TOPIC     Find packages matching a given topic keyword.
 r           Display the Emacs manual in Info mode.
 s           Display contents of current syntax table, plus explanations.

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Alexis]

Kelly Dean writes:

> I originally proposed this a couple years ago:
> https://lists.gnu.org/archive/html/emacs-devel/2012-12/msg00165.html

+1 for adding this functionality. At the moment i'm using the following
for exploring (a) the functionality provided by various Emacs
subsystems/packages, and (b) the potential customisations available:

    (defun list-symbols-with-prefix (prefix)
      "Create a buffer listing functions and variables with prefix PREFIX."
      (interactive "sPrefix: ")
      (let ((candidates (sort (all-completions prefix obarray) #'string<)))
        (switch-to-buffer (generate-new-buffer "*Symbols*"))
        (dolist (c candidates)
          (let ((s (intern c)))
            (cond
             ((fboundp s)
              (insert (concat (symbol-name s) " <f>\n")))
             ((boundp s)
              (insert (concat (symbol-name s) " <v>\n")))
             (t))))
        (beginning-of-buffer)
        (local-set-key (kbd "RET") 'doc-for-symbol-at-point)))


Alexis.

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Stefan Monnier]

> I've been using this patch since the time I wrote it, and find it
> handy. I rarely use «C-h v» or «C-h f» anymore.

Looks good to me,


        Stefan

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Kelly Dean]

Stefan Monnier wrote:
>> I've been using this patch since the time I wrote it, and find it
>> handy. I rarely use «C-h v» or «C-h f» anymore.
>
> Looks good to me,

What do I need to do with this patch? Send it to bug-gnu-emacs for a ticket number?

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

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On 28 Jan 2015 08:25, "Kelly Dean" <kelly@prtime.org> wrote:
>
> Stefan Monnier wrote:
> >> I've been using this patch since the time I wrote it, and find it
> >> handy. I rarely use «C-h v» or «C-h f» anymore.
> >
> > Looks good to me,
>
> What do I need to do with this patch? Send it to bug-gnu-emacs for a
ticket number?

Seems like it was well received.
If no one else picks this up, I'll test and merge it in for you on Friday
(getting on a reeeally long plane trip today).

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Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

Forgot to ask, have you assigned copyright?

2015-01-28 8:25 GMT-02:00 Kelly Dean <kelly@prtime.org>:
> Stefan Monnier wrote:
>>> I've been using this patch since the time I wrote it, and find it
>>> handy. I rarely use «C-h v» or «C-h f» anymore.
>>
>> Looks good to me,
>
> What do I need to do with this patch? Send it to bug-gnu-emacs for a ticket number?
>

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

Nevermind, I see you said that in your first message.

2015-01-30 18:05 GMT-02:00 Artur Malabarba <bruce.connor.am@gmail.com>:
> Forgot to ask, have you assigned copyright?
>
> 2015-01-28 8:25 GMT-02:00 Kelly Dean <kelly@prtime.org>:
>> Stefan Monnier wrote:
>>>> I've been using this patch since the time I wrote it, and find it
>>>> handy. I rarely use «C-h v» or «C-h f» anymore.
>>>
>>> Looks good to me,
>>
>> What do I need to do with this patch? Send it to bug-gnu-emacs for a ticket number?
>>

patches: emacs-devel@ vs. debbugs.gnu.org

[Ivan Shmakov]

>>>>> Kelly Dean <kelly@prtime.org> writes:
>>>>> Stefan Monnier wrote:

 >>> I've been using this patch since the time I wrote it, and find it
 >>> handy. I rarely use «C-h v» or «C-h f» anymore.

 >> Looks good to me,

 > What do I need to do with this patch?  Send it to bug-gnu-emacs for a
 > ticket number?

	IMO, it never harms to have a bug# assigned to the case, as it
	allows for everything related to be linked to a single URI.

	As to /how/ to file bug reports, – my own preference is to send
	them to submit@ (/not/ bug-gnu-emacs@), as it allows me to
	specify Severity: and possibly Version: and Tags:.  Like:

Subject: hello.el: says goodbye 
To: submit at debbugs dot gnu dot org

Package:  emacs
Version:  24.4
Severity: minor
Tags: patch

    [The report comes here.  The patch is in a separate MIME part.]

-- 
FSF associate member #7257  http://boycottsystemd.org/  … 3013 B6A0 230E 334A

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Kelly Dean]

Artur Malabarba wrote:
> If no one else picks this up, I'll test and merge it in for you on Friday

Was this applied? It doesn't appear to be in trunk.

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

> > If no one else picks this up, I'll test and merge it in for you on Friday
>
> Was this applied? It doesn't appear to be in trunk.

Not yet, but I haven't forgotten about it. It just didn't apply
cleanly and I haven't had time to look into it.

Would you like to recreate the patch from current master?


Here's the apply output

$ git apply descfunorvar.patch
error: patch failed: lisp/help.el:215
error: lisp/help.el: patch does not apply

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Kelly Dean]

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Artur Malabarba wrote:
> Not yet, but I haven't forgotten about it. It just didn't apply
> cleanly and I haven't had time to look into it.
>
> Would you like to recreate the patch from current master?
>
>
> Here's the apply output
>
> $ git apply descfunorvar.patch
> error: patch failed: lisp/help.el:215
> error: lisp/help.el: patch does not apply

That's just Git being stupid. The «patch» program works fine.

Updated patch attached below so even Git can handle it.


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--- lisp/help-fns.el
+++ lisp/help-fns.el
@@ -930,6 +930,37 @@
 
 
 ;;;###autoload
+(defun describe-function-or-variable (symbol &optional buffer frame)
+  "Display the full documentation of the function or variable SYMBOL.
+If SYMBOL is a variable and has a buffer-local value in BUFFER or FRAME
+\(default to the current buffer and current frame), it is displayed along
+with the global value."
+  (interactive
+   (let* ((v-or-f (variable-at-point))
+	 (found (symbolp v-or-f))
+	 (v-or-f (if found v-or-f (function-called-at-point)))
+	 (found (or found v-or-f))
+	 (enable-recursive-minibuffers t)
+	 val)
+     (setq val (completing-read (if found
+				    (format
+				     "Describe function or variable (default %s): " v-or-f)
+				  "Describe function or variable: ")
+				obarray
+				(lambda (vv)
+				  (or (fboundp vv)
+				      (get vv 'variable-documentation)
+				      (and (boundp vv) (not (keywordp vv)))))
+				t nil nil
+				(if found (symbol-name v-or-f))))
+     (list (if (equal val "")
+	       v-or-f (intern val)))))
+  (if (not (symbolp symbol)) (message "You didn't specify a function or variable")
+    (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
+    (unless (frame-live-p frame) (setq frame (selected-frame)))
+    (help-xref-interned symbol buffer frame)))
+
+;;;###autoload
 (defun describe-syntax (&optional buffer)
   "Describe the syntax specifications in the syntax table of BUFFER.
 The descriptions are inserted in a help buffer, which is then displayed.
--- lisp/help-mode.el
+++ lisp/help-mode.el
@@ -621,10 +621,13 @@
 
 \f
 ;; Additional functions for (re-)creating types of help buffers.
-(defun help-xref-interned (symbol)
+
+;;;###autoload
+(defun help-xref-interned (symbol &optional buffer frame)
   "Follow a hyperlink which appeared to be an arbitrary interned SYMBOL.
 Both variable, function and face documentation are extracted into a single
-help buffer."
+help buffer. If SYMBOL is a variable, include buffer-local value for optional
+BUFFER or FRAME."
   (with-current-buffer (help-buffer)
     ;; Push the previous item on the stack before clobbering the output buffer.
     (help-setup-xref nil nil)
@@ -640,7 +643,7 @@
 			  (get symbol 'variable-documentation))
 		  ;; Don't record the current entry in the stack.
 		  (setq help-xref-stack-item nil)
-		  (describe-variable symbol))))
+		  (describe-variable symbol buffer frame))))
       (cond
        (sdoc
 	;; We now have a help buffer on the variable.
--- lisp/help.el
+++ lisp/help.el
@@ -95,6 +95,7 @@
     (define-key map "k" 'describe-key)
     (define-key map "l" 'view-lossage)
     (define-key map "m" 'describe-mode)
+    (define-key map "o" 'describe-function-or-variable)
     (define-key map "n" 'view-emacs-news)
     (define-key map "p" 'finder-by-keyword)
     (define-key map "P" 'describe-package)
@@ -218,6 +219,7 @@
 m           Display documentation of current minor modes and current major mode,
               including their special commands.
 n           Display news of recent Emacs changes.
+o SYMBOL    Display the given function or variable's documentation and value.
 p TOPIC     Find packages matching a given topic keyword.
 P PACKAGE   Describe the given Emacs Lisp package.
 r           Display the Emacs manual in Info mode.

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

Pushed.
Thanks for the patch, Kelly.

2015-02-05 1:59 GMT-02:00 Kelly Dean <kelly@prtime.org>:
> Artur Malabarba wrote:
>> Not yet, but I haven't forgotten about it. It just didn't apply
>> cleanly and I haven't had time to look into it.
>>
>> Would you like to recreate the patch from current master?
>>
>>
>> Here's the apply output
>>
>> $ git apply descfunorvar.patch
>> error: patch failed: lisp/help.el:215
>> error: lisp/help.el: patch does not apply
>
> That's just Git being stupid. The «patch» program works fine.
>
> Updated patch attached below so even Git can handle it.
>

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Dmitry Gutov]

On 02/05/2015 08:33 PM, Artur Malabarba wrote:
> Pushed.
> Thanks for the patch, Kelly.

Why only variables and functions?

We can also describe faces and packages (features).

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Kelly Dean]

Artur Malabarba wrote:
> Pushed.

Thanks. (Commit# 55eb7281).

Is the repository supposed to record the difference between author and committer in Git commit objects? Or does that go only in the ChangeLog file?

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Dmitry Gutov]

On 02/06/2015 08:23 AM, Kelly Dean wrote:
> Artur Malabarba wrote:
>> Pushed.
>
> Thanks. (Commit# 55eb7281).
>
> Is the repository supposed to record the difference between author and committer in Git commit objects? Or does that go only in the ChangeLog file?

Yes, it's supposed to. Using the --author git argument, or the Author: 
header when committing from VC.

Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Artur Malabarba]

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>> Is the repository supposed to record the difference between author and
committer in Git commit objects? Or does that go only in the ChangeLog file?
>
> Yes, it's supposed to. Using the --author git argument, or the Author:
header when committing from VC.

My bad, I thought the Change Log was enough.

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Re: [Old patch] Unify fn and var help to make learning elisp a little easier

[Stefan Monnier]

> My bad, I thought the Change Log was enough.

If you use C-c C-a from the *VC-Log* buffer, the ChangeLog info should
automatically be turned into the proper "Author:" header (which then
gets turned into the "--author" argument).


        Stefan