Re: [Groff] [Groff & Heirloom] tbl problem with backslashes

[Mike Bianchi]

On Sun, Aug 31, 2014 at 11:25:28PM -0500, Blake McBride wrote:
> I found that Groff and Heirloom handle backslashes in tables differently.
>  I actually think both are wrong, but I am not sure.  My input is as
> follows:
> 
> .TS
> a a .
> INPUT PRODUCES
> \\\\ \\
> abc def
> .TE
> 
> 
> 
> I am processing it with tbl & troff but no macro packages.  They produce
> different results - both unexpected by me.  What I am trying to produce is
> as follows:
> 
> INPUT    PRODUCES
> \\       \
> abc      def
> 
> 
> (Yes, I am using tabs between the columns on the real input file.)


You've run into what (I think) was first stated as "Kernighan's Lemma"
which went something like:

        In troff, the number of  /  characters necessary to output a single
         /  character grows exponentially with macro depth.


This is why the  \e  escape was created:

        ... \e represents the current escape character.
        To get a backslash glyph, use \(rs or \[rs].
                                                        groff(7)


Brian:  I hope I represented this accurately.  ;)

-- 
 Mike Bianchi
 Foveal Systems

 973 822-2085

 address@hidden
 http://www.AutoAuditorium.com
 http://www.FovealMounts.com