Punctuation in LaTeX formulas

Question

It seems to be common practice, when writing mathematics, to add punctuation to displayed formulas.

Is there any trick to avoid putting the punctuation mark inside the formula?

I want to avoid

Consider the function
\[ \sin(x).\]

I'd rather have something like:

Consider the function
\[ \sin(x)\].

But of course the full stop is displayed below the formula.

Is there a clever way to separate formulas and punctuation in LaTeX?

Answer 1

\catcode`\@=11 
\let\seveendformula\]
\def\]{\@ifnextchar.\PointAndEndFormula\seveendformula}
\def \PointAndEndFormula #1{.\seveendformula}
\catcode`\@=12 

Add

More complex solution works with .,?!;: :

\catcode`\@=11 
\def\addtopunct#1{\expandafter\let\csname punct@\meaning#1\endcsname\let}
\addtopunct{.}    \addtopunct{,}    \addtopunct{?}
\addtopunct{!}    \addtopunct{;}    \addtopunct{:}

\let\seveendformula\]
\def\PunctAndEndFormula #1{#1\seveendformula}
\def\]{\futurelet\punctlet\checkpunct@i}
\def\checkpunct@i{\expandafter\ifx\csname punct@\meaning\punctlet\endcsname\let  
       \expandafter\PunctAndEndFormula 
       \else \expandafter\seveendformula\fi}
\catcode`\@=12