[OS X TeX] Emacs 22.92, %! and TeXShop

[Thomas Kiffe]

On Jan 26, 2007, at 12:03 PM, Jens Noeckel wrote:

>
> On Jan 26, 2007, at 2:06 AM, Stephen Moye wrote:
>
>>
>> On Jan 26, 2007, at 12:12 AM, Jens Noeckel wrote:
>>
>>>
>>> On Jan 25, 2007, at 8:49 PM, Jens Noeckel wrote:
>>>
>>>>
>>>> On Jan 25, 2007, at 6:49 PM, Stephen Moye wrote:
>>>>
>>>>> On Jan 25, 2007, at 9:10 PM, Jens Noeckel wrote:
>>>>>
>>>>>>
>>>>>> On Jan 25, 2007, at 5:41 PM, Stephen Moye wrote:
>>>>>>
>>>>>>> On Jan 25, 2007, at 8:34 PM, Stephen Moye wrote:
>>>>>>>
>>>>>>>> I just started using emacs 22.92 -- I have been using emacs  
>>>>>>>> 22.50. Unlike v22.50, when I open a TeXShop TeX file with  
>>>>>>>> emacs 22.92, it is opened as a PostScript file. I imagined  
>>>>>>>> that it had something to do with the first line of the file:
>>>>>>>>
>>>>>>>> 	%!TEX TS-program = latex
>>>>>>>>
>>>>>>>> Sure enough, I went digging using
>>>>>>>>
>>>>>>>> 	C-h v auto-mode-alist
>>>>>>>>
>>>>>>>> and found a line in files.el:
>>>>>>>>
>>>>>>>> 	("%![^V]" . ps-mode)
>>>>>>>>
>>>>>>>> in addition to what I expected:
>>>>>>>>
>>>>>>>> 	("\\.[tT]e[xX]\\'" . tex-mode)
>>>>>>>>
>>>>>>>> So emacs is looking inside the file to make a better guess  
>>>>>>>> about what kind of file it is. I tried changing
>>>>>>>>
>>>>>>>> 	("%![^V]" . ps-mode)
>>>>>>>>
>>>>>>>> to
>>>>>>>>
>>>>>>>> 	("%![^VT]" . ps-mode)
>>>>>>>>
>>>>>>>> but that did not work.
>>>>>>>>
>>>>>>>> I really like emacs 22.nn, but this is a bit of a bother.  
>>>>>>>> Can I put something in my .emacs file to counter this  
>>>>>>>> unwanted cleverness? I know that I can put
>>>>>>>>
>>>>>>>> 	%-*-latex-*-
>>>>>>>>
>>>>>>>> as the first line of the file and both emacs and TeXShop  
>>>>>>>> will be happy, but that seems an unnecessary complication.
>>>>>>>>
>>>>>>>> Any suggestions? Or, alternatively, where else should I more  
>>>>>>>> appropriately post this query?
>>>>>>>>
>>>>>>>> Thank you for any insights.
>>>>>>>
>>>>>>> Sorry, but I should have mentioned that I am using emacs  
>>>>>>> under X11.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Stephen
>>>>>>>
>>>>>>
>>>>>> Stephen,
>>>>>> not knowing what exactly is in your .emacs already, I would  
>>>>>> suggest adding the line
>>>>>>
>>>>>>           (setq auto-mode-alist (cons '("\\.tex$" . tex-mode)  
>>>>>> auto-mode-alist))
>>>>>>
>>>>>> as close to the end of .emacs as possible (so that it doesn't  
>>>>>> get overridden by other associations - the order of these  
>>>>>> things matters).
>>>>>>
>>>>>> Jens
>>>>>
>>>>> I placed the line you suggested at the very end of my .emacs  
>>>>> file (which has very little in it), but a TeX file with %! at  
>>>>> the top still opened as a PostScript file.
>>>>>
>>>>> I am puzzled. Shouldn't the extension take precedence over  
>>>>> anything else? Surely a .tex file is almost certainly not going  
>>>>> to be a PostScript file...
>>>>>
>>>>> Anyway, thank you for the suggestion though.
>>>>>
>>>>> Stephen
>>>>>
>>>>> PS I did make the discovery that if the first line of the TeX  
>>>>> file is empty and the *second* line begins with %! then the  
>>>>> emacs mechanism is fooled and the file opens in TeX mode. Hmmmm...
>>>>
>>>>
>>>> Ah, I just saw in the documentation that the magic-mode-alist  
>>>> takes precedence over the auto-mode-alist. I had not encountered  
>>>> this problem before, but I can reproduce it now with Carbon  
>>>> Emacs from fink. Here is something that fixes the problem: if  
>>>> you put this line in your .emacs, it will be stricter about what  
>>>> it considers as postscript:
>>>>
>>>> (mapc (lambda (pair) (if (eq (cdr pair) 'ps-mode) (setcar pair  
>>>> '"%!PS[^V]"))) magic-mode-alist)
>>>>
>>>> Now you have to have %!PS at the start to make it a PS file.  
>>>> What this code does is simply to search the magic-mode-alist for  
>>>> the ps-mode definition and replace the condition for recognizing  
>>>> it. This worked for me - hope it solves your problem, too.
>>>>
>>>> Jens
>>>>
>>>
>>> One more change:
>>> to avoid an error when using other emacs versions that don't  
>>> define magic-mode-alist, enclose everything in an if statement:
>>>
>>> (if (fboundp 'magic-mode-alist)
>>> (mapc (lambda (pair) (if (eq (cdr pair) 'ps-mode) (setcar pair  
>>> '"%!PS[^V]"))) magic-mode-alist))
>>>
>>> I think that should cover everything now...
>>> Jens
>>
>> Thank you -- that worked perfectly. I'll have to study and learn  
>> from your fix, so thank you again for explaining it to me.
>>
>>
> Stephen,
>
> great to know it worked. By the way, this lisp code could be  
> translated almost one-to-one to Mathematica. So if you know  
> Mathematica, you known lisp (and vice versa) - except that the  
> keywords are different. Don't know if this helps... if not, here is  
> a link for learning emacs (and lisp):
>
> http://xahlee.org/emacs/emacs_fun.html
>
> Regards,
> Jens

For many years the symbols
%!
at the beginning of a file has been required to designate a file as a  
Postscript file. Emacs is
just following this convention when trying to recognize a Postscript  
file. Rather than having to
modify or reconfigure Emacs (and possibly other programs) it is  
TeXShop which should respect accepted
conventions and change its notation.

Tom



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