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.robin...@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