Re: PATCH: proposed improvements to org-src-mode

[Carsten Dominik <carsten.dominik@gmail.com>]

Hi Dan,

thank you for studying and describing these issues, and for proposing  
a patch.

I am not sure that the implementation you offer is the cleanest
possibile, I definitely do not want to attach a file to this
temporary editing buffer.  It is probably better to install
a kill-buffer-hook to force the query, for example, or even
to advise the save-buffers-kill-terminal function to
handle the special case.

First of all, in reading your mail I have a few problems
understanding exactly what you mean, because I have the feeling
that you do not clearly distinguish between `C-x s' and `C-x C-s'.   
Because you write that `C-x s' is bound to `org-edit-src-save'
which is is not.

Could you please review your post to make sure that you
are using the correct keys?  The I will comment further.

Thanks.

- Carsten


On Aug 11, 2009, at 6:44 PM, Dan Davison wrote:

> I'm attaching a patch which attempts to make some improvements to
> org-src-mode. A quick recap: currently, C-c ' on a source code block
> displays the code in a language major mode buffer with minor mode
> org-src-mode, which features the following two useful key-bindings:
>
> | C-x s | org-edit-src-save | save the code in the source code block  
> in the parent org file |
> | C-c ' | org-edit-src-exit | return to the parent org file with new  
> code                   |
>
> Furthermore, while the edit buffer is alive, the originating code  
> block
> is subject to a special overlay which links to the edit buffer when  
> you
> click on it. This is all excellent, and I use it every day, but I  
> think
> there's still a couple of improvements that we should make.
>
> Specifically, I'm proposing that the following are bugs:
>
> * Proposed bug I
>      C-x k kills the edit buffer without questions; the overlay
>      remains, but now links to a deleted buffer.
> * Proposed bug II
>      C-x C-c kills a modified edit buffer silently, without offering  
> to
>      save your work. I have lost work like that a number of times
>      recently.
> * Proposed bug III
>      C-x s does not offer to save a modified edit buffer
>
> The attached patch does the following.
> - C-x s offers to save edit buffers
> - C-x C-c offers to save edit buffers
> - C-x k warns that you're killing an edit buffer
> - If you do kill an edit buffer, the overlay in the parent buffer is  
> removed
> - Edit buffers are named *Org Src <orgbuf>[<lang>]*, where
>  <orgbuf> is the name of the org-mode buffer containing this
>  source code block, and lang is the language major mode.
> - An internal detail is that org-edit-src-save is added to the
>  write-contents-functions list, which means that it is no longer
>  necessary to explicitly remap C-x C-s to org-edit-src-save
>
> * Notes
>  This patch gives the desired behaviour, at the cost of being forced  
> to
>  assign a buffer-file-name to the edit buffer. The consequence is that
>  the edit buffer is considered to always be modified, since a file of
>  that name is never actually written to (doesn't even exist). I didn't
>  manage to come up with a way to trick emacs into holding the
>  appropriate beliefs about whether the buffer had been modified. But  
> in
>  any case, I think there's an argument that these modifications
>  warnings are a good thing, because one should not leave active edit
>  buffers around: you should always have exited with C-c ' first.
>
> Just in case it is helpful, I am including the notes I made in the
> course of making these changes at the very bottom of the email.
>
> Dan
>
> p.s. In these two lines:
> -  (unless (string-match "\\`*Org Edit " (buffer-name (current- 
> buffer)))
> -    (error "This is not an sub-editing buffer, something is  
> wrong..."))
> +  (unless org-edit-src-from-org-mode
> +    (error "This is not a sub-editing buffer, something is  
> wrong..."))
>
> I assumed that org-edit-src-from-org-mode was an appropriate test. But
> that may be incorrect as I am not certain what the intention was for
> that variable.
>
> --8<---------------cut here---------------start------------->8---
> diff --git a/lisp/org-src.el b/lisp/org-src.el
> index 2a6c087..a5816d2 100644
> --- a/lisp/org-src.el
> +++ b/lisp/org-src.el
> @@ -113,7 +113,6 @@ but which mess up the display of a snippet in  
> Org exported files.")
>
> (defvar org-src-mode-map (make-sparse-keymap))
> (define-key org-src-mode-map "\C-c'" 'org-edit-src-exit)
> -(define-key org-src-mode-map "\C-x\C-s" 'org-edit-src-save)
> (defvar org-edit-src-force-single-line nil)
> (defvar org-edit-src-from-org-mode nil)
> (defvar org-edit-src-picture nil)
> @@ -168,7 +167,8 @@ the edited version."
> 	    (if (boundp 'org-edit-src-overlay)
> 		(org-delete-overlay org-edit-src-overlay)))
> 	  (kill-buffer buffer))
> -	(setq buffer (generate-new-buffer "*Org Edit Src Example*"))
> +	(setq buffer (generate-new-buffer
> +		      (concat "*Org Src " (file-name-nondirectory buffer-file- 
> name) "[" lang "]*")))
> 	(setq ovl (org-make-overlay beg end))
> 	(org-overlay-put ovl 'face 'secondary-selection)
> 	(org-overlay-put ovl 'edit-buffer buffer)
> @@ -186,8 +186,7 @@ the edited version."
> 				'(display nil invisible nil intangible nil))
> 	(org-do-remove-indentation)
> 	(let ((org-inhibit-startup t))
> -	  (funcall lang-f)
> -	  (org-src-mode))
> +	  (funcall lang-f))
> 	(set (make-local-variable 'org-edit-src-force-single-line) single)
> 	(set (make-local-variable 'org-edit-src-from-org-mode) org-mode-p)
> 	(when lfmt
> @@ -201,6 +200,7 @@ the edited version."
> 	(org-set-local 'org-edit-src-end-marker end)
> 	(org-set-local 'org-edit-src-overlay ovl)
> 	(org-set-local 'org-edit-src-nindent nindent)
> +	(org-src-mode)
> 	(and org-edit-src-persistent-message
> 	     (org-set-local 'header-line-format msg)))
>       (message "%s" msg)
> @@ -400,12 +400,13 @@ the language, a switch telling of the content  
> should be in a single line."
> (defun org-edit-src-exit ()
>   "Exit special edit and protect problematic lines."
>   (interactive)
> -  (unless (string-match "\\`*Org Edit " (buffer-name (current- 
> buffer)))
> -    (error "This is not an sub-editing buffer, something is  
> wrong..."))
> +  (unless org-edit-src-from-org-mode
> +    (error "This is not a sub-editing buffer, something is  
> wrong..."))
>   (let ((beg org-edit-src-beg-marker)
> 	(end org-edit-src-end-marker)
> 	(ovl org-edit-src-overlay)
> 	(buffer (current-buffer))
> +	(buffer-file-name nil)
> 	(nindent org-edit-src-nindent)
> 	code line)
>     (untabify (point-min) (point-max))
> @@ -444,7 +445,6 @@ the language, a switch telling of the content  
> should be in a single line."
>     (switch-to-buffer (marker-buffer beg))
>     (kill-buffer buffer)
>     (goto-char beg)
> -    (org-delete-overlay ovl)
>     (delete-region beg end)
>     (insert code)
>     (goto-char beg)
> @@ -464,6 +464,18 @@ the language, a switch telling of the content  
> should be in a single line."
>     (goto-char (min p (point-max)))
>     (message (or msg ""))))
>
> +(defun org-src-mode-configure-buffer ()
> +  (setq buffer-offer-save t)
> +  (setq buffer-file-name
> +	(concat (buffer-file-name (marker-buffer org-edit-src-beg-marker))
> +		"[" (buffer-name) "]"))
> +  (set (if (featurep 'xemacs) 'write-contents-hooks 'write-contents- 
> functions)
> +       '(org-edit-src-save))
> +  (org-add-hook 'kill-buffer-hook
> +		'(lambda () (org-delete-overlay org-edit-src-overlay)) nil 'local))
> +
> +(org-add-hook 'org-src-mode-hook 'org-src-mode-configure-buffer)
> +
> (provide 'org-src)
>
> ;; arch-tag: 6a1fc84f-dec7-47be-a416-64be56bea5d8
> --8<---------------cut here---------------end--------------->8---
>
> * Notes on patch
> *** write-contents-functions
>    A good start seems to be to use org-src-mode-hook to add
>    org-edit-src-save to the write-contents-functions list. This
>    means that when it comes to saving, org-edit-src-save will be
>    called and no subsequent attempt will be made to save the buffer
>    in the normal way. (This should obviate the remapping of C-x C-s
>    to org-edit-src-save in org-src.el)
> *** buffer-offer-save
>    We also want to set this to t.
>
> *** Where does this get us?
>
>    - C-x s still does *not* offer to save the edit buffer. That's
>      because buffer-file-name is nil.
>
>    - C-x C-c does ask us whether we want to save the
>      edit buffer. However, since buffer-file-name is nil it asks us
>      for a file name. The check in org-edit-src-exit throws an error
>      unless the buffer is named '* Org Edit '...
>
>    - C-x k kills the buffer silently, leaving a broken overlay
>      link. If buffer-file-name were set, it would have warned that
>      the buffer was modified.
>
> *** buffer-file-name
>    So, that all suggests that we need to set buffer-file-name, even
>    though we don't really want to associate this buffer with a file
>    in the normal way. As for the file name, my current suggestion
>    is parent-org-filename[edit-buffer-name].
>
>    [I had to move the (org-src-mode) call to the end of
>    org-edit-src-code to make sure that the required variables were
>    defined when the hook was called.]
>
> *** And so where are we now?
>    - C-x s *does* offer to save the edit buffer, but in saving
>      produces a warning that the edit buffer is modified.
>    - C-x k now gives a warning that the edit buffer is modified
>      (even if it's not).
>    - C-x C-c is working as desired, except that again we get
>      warnings that the edit buffer is modified, once when we save,
>      and again just before exiting emacs.
>    - And C-c ' now issues a warning that the edit buffer is
>      modified when we leave it, which we don't want.
> *** So, we need to get rid of the buffer modification warnings.
>    I've made buffer-file-name nil inside the let binding in
>    org-edit-src-exit.
> *** And?
>    - C-x s behaves as desired, except that as was already the case,
>      the edit buffer is always considered modified, and so repeated
>      invocations keep saving it.
>    - As was already the case, C-x k always gives a warning that the
>      edit buffer has been modified.
>    - C-x C-c is as desired (offers to save the edit buffer) except
>      that it warns of the modified buffer just before exiting.
>    - C-c ' is as it should be (silent)
>
>
> Carsten Dominik <carsten.dominik@gmail.com> writes:
>
>> Hi Dan,
>>
>> On Jun 2, 2009, at 5:02 PM, Dan Davison wrote:
>>
>>> Following on from the recent improvements to the *Org Edit Src
>>> Example*
>>> buffer, I have one more proposal: I have remapped C-x C-s so that it
>>> saves the code in the org buffer, rather than offering to save the
>>> Edit
>>> buffer itself (as it used to be with the indirect edit buffer). I  
>>> find
>>> this essential, although I recognise that remapping C-x C-s is a
>>> rather
>>> radical thing to do to an emacs buffer.
>>
>>
>> But allowed:  From the Emacs lisp docs, under Major Mode Conventions:
>>
>>     It is legitimate for a major mode to rebind a standard key
>>     sequence if it provides a command that does "the same job" in a
>>     way better suited to the text this mode is used for.
>>
>> I'd say, your's is a perfect example for this rule.
>>
>>
>>> I am using the simple-minded approach below; it seems to work fine  
>>> (I
>>> don't even notice a flicker -- should I be surprised at that?),  
>>> but if
>>> someone can suggest an improved implementation I'd be happy to learn
>>> how
>>> it should be done (perhaps there are buffer variables other than  
>>> point
>>> and mark that I should restore? Is there a general mechanism I  
>>> should
>>> use for this?).
>>>
>>> Dan
>>>
>>> (defun org-edit-src-save ()
>>> "Update the parent org buffer with the edited source code, save
>>> the parent org-buffer, and return to the source code edit
>>> buffer."
>>> (interactive)
>>> (let ((p (point))
>>> 	(m (mark)))
>>>   (org-edit-src-exit)
>>>   (save-buffer)
>>>   (org-edit-src-code)
>>>   (set-mark m)
>>>   (goto-char p)))
>>
>> This is already excellent.  I have changed it only slightly,
>> in order to get a better message when this command finishes, and
>> because `push-mark' should be used here instead of `set-mark'.
>>
>> (defun org-edit-src-save ()
>>  "Save parent buffer with current state source-code buffer."
>>  (interactive)
>>  (let ((p (point)) (m (mark)) msg)
>>    (org-edit-src-exit)
>>    (save-buffer)
>>    (setq msg (current-message))
>>    (org-edit-src-code)
>>    (push-mark m 'nomessage)
>>    (goto-char p)
>>    (message (or msg ""))))
>>
>> I have added your code, thanks.
>>
>> - Carsten