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

[Jens Noeckel]

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




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