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

[Jens Noeckel]

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


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