Re: Changing of line format and undo

[Lennart Borgman <lennart.borgman.073@student.lu.se>]

David Kastrup wrote:
> Lennart Borgman <lennart.borgman.073@student.lu.se> writes:
>
>   
>> David Kastrup wrote:
>>     
>>> Lennart Borgman <lennart.borgman.073@student.lu.se> writes:
>>>
>>>   
>>>       
>>>> Eli Zaretskii wrote:
>>>>     
>>>>         
>>>>>> Date: Wed, 21 Jun 2006 00:15:17 +0200
>>>>>> From: Lennart Borgman <lennart.borgman.073@student.lu.se>
>>>>>>
>>>>>> If you change line endings this change is not saved to undo. Is
>>>>>> this the expected behaviour?
>>>>>>             
>>>>>>             
>>>>> If you mean "C-x RET f", then it doesn't really change anything.  It
>>>>> just sets a buffer-local variable to some value.  So there's nothing
>>>>> to undo.
>>>>>         
>>>>>           
>>>> That is an internal Emacs perpective. From a users point of view there
>>>> is truly a change. If you for example change the line endings the file
>>>> will be saved with this new line endings.
>>>>
>>>> BTW should not changes of this kind also set the buffer to modified?
>>>>     
>>>>         
>>> What makes you think they don't?
>>>
>>>   
>>>       
>> Test this for example:
>>
>>    (defun test-set-eol()
>>      (interactive)
>>      (let* ((coding buffer-file-coding-system)
>>             (new-coding (coding-system-change-eol-conversion coding 2)))
>>        (setq buffer-file-coding-system new-coding)))
>>     
>
> Very funny.  setq most certainly does not trigger effects like a
> changed buffer modification flag.  But setq is not a user-level
> command.  Here is one that is:
>   
Thanks, you are right ;-) Now I see what Eli meant. I still believe that 
everything that can result in changing an external file should go into 
the undo history but this is really a corner case of course.