help: howto call ediff from elisp, interactive and multiple args ...

help: howto call ediff from elisp, interactive and multiple args ...

[Peter Daum]

Sorry, I couldn't find an appropriate subject line:

I have to compare many similar binary files and the best tool I could
find so far for this purpose is a combination of emacs, hexl-mode and
ediff. Because this involves far too much typing, I am trying to write a
little lisp function to set up everything. I already know several ways
how not to do this ;-)

(defun hexl-ediff (file1 file2)
  "hexl-find 2 files and run ediff on them"
  (interactive "fFile 1:" "fFile2:")
  (hexl-find-file file1)
  (let*
      (
       (buffer1 (last-buffer))
       (bn1 (buffer-name buffer1))
       (void (hexl-find-file file2))
       (buffer2 (last-buffer))
       (bn2 (buffer-name buffer2))
       (void (message "b1: %s b2: %s" bn1 bn2))
       )
    (ediff-buffers bn1 bn2)
    ))

There are several problems with this:

1) I could not find a way how to interactively call this with 2 files.
I'll get prompted for the 1st file and then I run into an error about
the wrong #args without any chance to enter the 2nd file name
2) More severe: I could not come up with any reliable way how to get the
names of the buffers that the calls to hexl-find-file created (the
desperate attempt with "last-buffer" will return "*Completions*" ;-)

Any ideas?

Regards,
                            Peter

Re: help: howto call ediff from elisp, interactive and multiple args ...

[Thierry Volpiatto]

Peter Daum <gator_ml@yahoo.de> writes:

> Sorry, I couldn't find an appropriate subject line:
>
> I have to compare many similar binary files and the best tool I could
> find so far for this purpose is a combination of emacs, hexl-mode and
> ediff. Because this involves far too much typing, I am trying to write a
> little lisp function to set up everything. I already know several ways
> how not to do this ;-)
>
> (defun hexl-ediff (file1 file2)
>   "hexl-find 2 files and run ediff on them"
>   (interactive "fFile 1:" "fFile2:")
>   (hexl-find-file file1)
>   (let*
>       (
>        (buffer1 (last-buffer))
>        (bn1 (buffer-name buffer1))
>        (void (hexl-find-file file2))
>        (buffer2 (last-buffer))
>        (bn2 (buffer-name buffer2))
>        (void (message "b1: %s b2: %s" bn1 bn2))
>        )
>     (ediff-buffers bn1 bn2)
>     ))
>
> There are several problems with this:
>
> 1) I could not find a way how to interactively call this with 2 files.
> I'll get prompted for the 1st file and then I run into an error about
> the wrong #args without any chance to enter the 2nd file name
> 2) More severe: I could not come up with any reliable way how to get the
> names of the buffers that the calls to hexl-find-file created (the
> desperate attempt with "last-buffer" will return "*Completions*" ;-)
>
> Any ideas?


(defun hexl-ediff (file1 file2)
  "hexl-find 2 files and run ediff on them"
  (interactive "fFile 1: \nfFile2:")
  (let ((buffer1 (progn
                     (hexl-find-file file1)
                     (buffer-name (current-buffer))))
        (buffer2 (progn
                     (hexl-find-file file2)
                     (buffer-name (current-buffer)))))
    (ediff-buffers buffer1 buffer2)))

> Regards,
>                             Peter
>
>
>

-- 
A+ Thierry
Get my Gnupg key:
gpg --keyserver pgp.mit.edu --recv-keys 59F29997 

Re: help: howto call ediff from elisp, interactive and multiple args ...

[Peter Daum]

> Peter Daum <gator_ml@yahoo.de> wrote:
>> I have to compare many similar binary files and the best tool I could
>> find so far for this purpose is a combination of emacs, hexl-mode and
>> ediff. Because this involves far too much typing, I am trying to write a
>> little lisp function to set up everything. I already know several ways
>> how not to do this ;-)
[...]
On 2010-11-13 20:16, Thierry Volpiatto wrote:
> (defun hexl-ediff (file1 file2)
>   "hexl-find 2 files and run ediff on them"
>   (interactive "fFile 1: \nfFile2:")
>   (let ((buffer1 (progn
>                      (hexl-find-file file1)
>                      (buffer-name (current-buffer))))
>         (buffer2 (progn
>                      (hexl-find-file file2)
>                      (buffer-name (current-buffer)))))
>     (ediff-buffers buffer1 buffer2)))

Exactly what I was looking for and it actually works ;-)

Thanks a lot!
                   Peter

Re: help: howto call ediff from elisp, interactive and multiple args ...

[Pascal J. Bourguignon]

Peter Daum <gator_ml@yahoo.de> writes:

> Sorry, I couldn't find an appropriate subject line:
>
> I have to compare many similar binary files and the best tool I could
> find so far for this purpose is a combination of emacs, hexl-mode and
> ediff. Because this involves far too much typing, I am trying to write a
> little lisp function to set up everything. I already know several ways
> how not to do this ;-)
>
> (defun hexl-ediff (file1 file2)
>   "hexl-find 2 files and run ediff on them"
>   (interactive "fFile 1:" "fFile2:")
>   (hexl-find-file file1)
>   (let*
>       (
>        (buffer1 (last-buffer))
>        (bn1 (buffer-name buffer1))
>        (void (hexl-find-file file2))
>        (buffer2 (last-buffer))
>        (bn2 (buffer-name buffer2))
>        (void (message "b1: %s b2: %s" bn1 bn2))
>        )
>     (ediff-buffers bn1 bn2)
>     ))
>
> There are several problems with this:
>
> 1) I could not find a way how to interactively call this with 2 files.
> I'll get prompted for the 1st file and then I run into an error about
> the wrong #args without any chance to enter the 2nd file name

Have you read the documentation of interactive?

Do you know how to get it?

What word don't you understand in: 

    "To get several arguments, concatenate the individual strings,
    separating them by newline characters."

?



> 2) More severe: I could not come up with any reliable way how to get the
> names of the buffers that the calls to hexl-find-file created (the
> desperate attempt with "last-buffer" will return "*Completions*" ;-)

Have you read the documentation of ediff-buffers?

(Do you know how to get it?)

Now, a lot of functions taking buffers will accept buffer names as
buffer designators, in particular commands, so it wouldn't be wrong, but
you don't have to find the names. Just pass the buffers.

Also see:  (info "(elisp)Buffer Names")


After find-file, or hexl-find-file, the current-buffer will be the one.

(defun hexl-ediff (file1 file2)
  "hexl-find 2 files and run ediff on them"
  (interactive "fFile 1\nfFile2:")
  (ediff-buffers (progn (hexl-find-file file1)
                        (current-buffer))
                 (progn (hexl-find-file file2)
                        (current-buffer))))


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.