What does 'missing \@ before...' error mean in vim?

Question

I get this strange behavior when I have capitals before a period, like so

    1 \documentclass{article}
    2 \begin{document}
>>  3 Another possible protein blah blah blah from GRIP/ABP. Blah Blah Blah
    4 \end{document}

The error I generally get in vim is:

blahblah.tex|3 error| missing `\@' before `.' in "ABP."

What does that mean? Why do I get it? How do I fix it?

Answer 1

The following hopefully answers your "abbreviated questions":

1. vim suggests inserting \@ before . in ...GRIP/ABP. So, do it! The reason here is that GRIP/ABP or any capitalized word before a period is usually an abbreviation. And, in some instances, abbreviations have periods, while some don't. To treat the end-of-abbreviation period as an end-of-sentence period, like it is in your case, use

   Another possible protein blah blah blah from GRIP/ABP\@. Blah Blah Blah
   

   Here is a visual of the effect if you don't use it:

   

   \documentclass{article}
   \begin{document}
   Another possible protein blah blah blah from GRIP/ABP. Blah Blah Blah \par
   Another possible protein blah blah blah from GRIP/ABP\@. Blah Blah Blah
   \end{document}​
   

   Note the difference in spacing after the period. The latter constitutes a larger-than-usual end-of-sentence period.

2. vim is smart and suggests you use it, since it is good style to have proper puntuation.

3. See 1.

_{The recursive nature of this non-art-like triptych reminds me of the acronym GNU.}