Re: \: re-enables hyphenation--should it?

[Larry Kollar]

It’s a space, which I would presume ends a word. A zero-width space,
by definition, but still a space. I think I’ve run into the same issue, and
put \% after the space to prevent hyphenation without thinking much
about it.

— Larry


> On Jul 24, 2020, at 11:40 PM, G. Branden Robinson 
> <g.branden.robinson@gmail.com> wrote:
> 
> It seems that \: does more than I expected, and I'm wondering if that's
> my fault or groff's fault.
> 
> Consider the following:
> 
>       .pl 1v
>       .ll 1u
>       .hy 4
>       http://metathesis.com/foobar.html
>       .sp 1v
>       \%http://metathesis.com/foobar.html
>       .sp 1v
>       \%http://metathesis.com/\:foobar.html
>       .sp 1v
>       \%http://\:metathesis.com/\:foobar.html
>       .sp 1v
>       \%http://\:\%metathesis.com/\:\%foobar.html
> 
> Running this through "nroff -Wbreak", I get:
> 
>       http://metathe‐
>       sis.com/foo‐
>       bar.html
> 
>       http://metathesis.com/foobar.html
> 
>       http://metathesis.com/
>       foo‐
>       bar.html
> 
>       http://
>       metathe‐
>       sis.com/
>       foo‐
>       bar.html
> 
>       http://
>       metathesis.com/
>       foobar.html
> 
> Notice how hyphens return at the first possible point after a '\:' is
> seen.
> 
> It appears that '\:' re-enables hyphenation.  I would expect hyphenation
> to resume at the end of the word, but the word hasn't ended yet.
> Without yet source diving, my guess is that the bit of state that '\%'
> sets is cleared after a line break.
> 
> Arguably, it should not be.  Only (I think) the next actual word space
> node should clear that bit of state.
> 
> If the above is correct behavior, then I need to update
> makevarescape.sed in the source tree and the explanation and example of
> \: in our Texinfo manual and man pages, because this detail is not
> documented.
> 
> But I think it's a bug.
> 
> What do y'all think?
> 
> Regards,
> Branden