[texhax] Smart periods?

[Uwe Lück]

Am Sonntag, den 04.11.2012, 12:59 -0500 schrieb Michael Barr:
> \subsection{This is a subsection}
> \subsection{This is a subsection.}
> \subsection{Is this a subsection?}
> \subsection{This is an amazing subsection!}
> and I would want to automatically add a period to the first form
> and leave the remaining three unchanged.
> This is also an issue for the starred version.  
> I have tried a couple of solutions, none of which quite worked.  
> Yet it seems like an obvious thing for someone to have dealt with.  

Instead of presenting a perfect answer soon, 
I would like to recommend reading the answers 
to your similar question on 
"The last character of a string"
on

    http://tug.org/pipermail/texhax/2010-January/

Cheers, 

    Uwe.