%%% word double-hyphenation
% (saw in Peter Szabo's papers)

How about this macro for an explicit hyphen that does not inhibit
further hyphenation within the word?  (It's not original with me; the
\TeX{}nique was first described by Knuth, I believe.)

\beginverbatim
\def\xhyphen{\leavevmode\nobreak-\hskip0pt }
\endverbatim

Let's compare the following two paragraphs:

\beginverbatim
\hsize=2.5in

How about this macro for an explicit hyphen that does not inhibit
further-hyphenation within the word?

How about this macro for an explicit hyphen that does not inhibit
further\xhyphen hyphenation within the word?
\endverbatim

\begingroup
\def\xhyphen{\leavevmode\nobreak-\hskip0pt }
\leftskip=2em \hsize=\dimexpr2em+2.5in\relax \parindent=1em

How about this macro for an explicit hyphen that does not inhibit
further-hyphenation within the word?
\par
How about this macro for an explicit hyphen that does not inhibit
further\xhyphen hyphenation within the word?
\par\endgroup

\bigskip All the magic is done by the \verb'\hskip0pt', which
essentially starts a new word as far as \TeX\ is concerned (in the
middle of the hyphenated word), thus giving it a new chance at
hyphenation. The \verb'\leavemode' merely avoids the penalty being added
to the vertical list, in case the macro is used at the beginning of a
paragraph.

