set-window-buffer bugs

set-window-buffer bugs

[jenia.ivlev]

Hello.

Using dired, I want find-buffer-other-window to open in the exact
same window. 

So I made this little program:


    (define-key dired-mode-map "o" 'dired-find-file-other-opened-window)

    (defun dired-find-file-other-opened-window ()
        (interactive)
        (set-window-buffer (frame-first-window) (dired-get-filename 'no-dir))
        (dired-find-file-other-window))
        

It turns out that you needed to have visited that file already for
this to work.


Here is the backtrace for when it doesnt work:

    Debugger entered--entering a function:
    * #<subr set-window-buffer>(#<window 3 on *Backtrace*> "String.h" nil)
    * apply(#<subr set-window-buffer> (#<window 3 on *Backtrace*> "String.h"))
    * set-window-buffer(#<window 3 on *Backtrace*> "String.h")
    dired-find-file-other-opened-window()
    dired-fnd-fl-otr-opn-wnd-keep-cursor()
    call-interactively(dired-fnd-fl-otr-opn-wnd-keep-cursor nil nil)
    command-execute(dired-fnd-fl-otr-opn-wnd-keep-cursor)

After pressing `d` again, I get:

    * command-error-default-function((wrong-type-argument bufferp nil) "" apply)

And here is a backtrace where it does work (the file has been previous visited):

    Debugger entered--entering a function:
    * window-buffer(#<window 3 on *Backtrace*>)
    * linum-after-scroll(#<window 3 on *Backtrace*> 1)
    * #<subr set-window-buffer>(#<window 3 on *Backtrace*> "String.c" nil)
    * apply(#<subr set-window-buffer> (#<window 3 on *Backtrace*> "String.c"))
    * set-window-buffer(#<window 3 on *Backtrace*> "String.c")
    dired-find-file-other-opened-window()
    dired-fnd-fl-otr-opn-wnd-keep-cursor()
    call-interactively(dired-fnd-fl-otr-opn-wnd-keep-cursor nil nil)
    command-execute(dired-fnd-fl-otr-opn-wnd-keep-cursor)



I mean, I don't get it. Why do I need to have visited the file before?
And in any case, how do I fix this? I just want it to open in the
(frame-first-window) that's all.


Thanks

Re: set-window-buffer bugs

[jenia.ivlev]

To see where this is useful, divide you screen like this:


|TEXT FILE | DIRED BUFFER
|          |-------------
|          |IBUFFER BUFFER



I want the files in dired to always open in the left most window.
So again this program works perfectly well for files that you have
visited before, but not for the files you've never open yet

Re: set-window-buffer bugs

[John Mastro]

jenia.ivlev <jenia.ivlev@gmail.com> wrote:
> Hello.
>
> Using dired, I want find-buffer-other-window to open in the exact
> same window.
>
> So I made this little program:
>
>
>     (define-key dired-mode-map "o" 'dired-find-file-other-opened-window)
>
>     (defun dired-find-file-other-opened-window ()
>         (interactive)
>         (set-window-buffer (frame-first-window) (dired-get-filename 'no-dir))
>         (dired-find-file-other-window))
>
>
> It turns out that you needed to have visited that file already for
> this to work.

[snip]

> I mean, I don't get it. Why do I need to have visited the file before?
> And in any case, how do I fix this? I just want it to open in the
> (frame-first-window) that's all.

Correct, the second argument to `set-window-buffer' must be a buffer (or
the name of a buffer), not the name of the file.

The distinction between buffers and files is an important one. As one
small practical consideration, there can be many files named "foo.txt",
but only one buffer named "foo.txt".

If you're not sure which (file or buffer) is appropriate for a given
function, check out its documentation (e.g. `C-h f set-window-buffer
RET'). In many cases, as with `set-window-buffer', the name itself gives
a hint.

All that said, I think the command below will do what you want. The
function `find-file-noselect' is the one that visits the file and
creates a buffer. If the file is already open, it returns the existing
buffer. It's a variant of `find-file' (the command bound to `C-x C-f')
with the difference that it doesn't display the buffer - useful to us
here because we want to handle that part ourselves.

(defun dired-find-file-other-opened-window ()
  (interactive)
  (let* ((file (dired-get-filename 'no-dir))
         (buffer (find-file-noselect file)))
    (set-window-buffer (frame-first-window) buffer)))

Hope that helps

-- 
john

Re: set-window-buffer bugs

[jenia.ivlev]

Great. Works perfectly.

Thanks a lot John