[Groff] Re: Error in meref.me?

[Robert Goulding]

On Tuesday, October 28, 2003, at 02:42 AM, Werner LEMBERG wrote:

> > I find that, in order to put the chapter/appendix number in the
> > header, I need a command like:
> >
> >   .++ A '\\\\\\\\n(ch''
> ...
> I have never used -me, so I can't verify that.  But what about using
> `\E' instead of `\e'?
>
>   .++ RA '''\En[ch].%'


Yes, it does work - thank you.  I've never tried it because I never 
really understood what \E did - am I right to say that this a backslash 
which is *only* interpreted at the very last moment, and is passed 
through however many levels of copy mode without interpretation?  So, 
conceivably, it could be used *whenever* traditional troff doubles 
backslashes?  If so, perhaps a note to that effect could be put in the 
groff_tmac  manpage, and it could be made a little more explicit in 
groff info.

Suggested change to groff_tmac.5.  At the end of the section on 
"Copy-in mode":

.P
As a GNU extension, the entire problem of when to double backslashes 
can be circumvented by using the \[rs]E escape sequence.
.
This is, in effect, a backslash which is only interpreted at the last 
possible moment.
.
Thus, in the example of positional parameters above, one can write 
\[rs]E$* instead of \[rs]\[rs]$*.
.
This alternative form becomes particularly useful when an escape 
sequence must copied-in two or three times.
.
Traditional
.B troff
then requires four or eight backslashes in order to prevent 
interpretation;
in GNU troff, a  single \[rs]E will suffice.