+ %
+ \gdef\codedash{\futurelet\next\codedashfinish}
+ \gdef\codedashfinish{%
+ \normaldash % always output the dash character itself.
+ %
+ % Now, output a discretionary to allow a line break, unless
+ % (a) the next character is a -, or
+ % (b) the preceding character is a -.
+ % E.g., given --posix, we do not want to allow a break after either -.
+ % Given --foo-bar, we do want to allow a break between the - and the b.
+ \ifx\next\codedash \else
+ \ifx\codedashprev\codedash
+ \else \discretionary{}{}{}\fi
+ \fi
+ % we need the space after the = for the case when \next itself is a
+ % space token; it would get swallowed otherwise. As in @code{- a}.
+ \global\let\codedashprev= \next
+ }