> I think moving to > .EQ > delim ## > .EN > is an alternative which is easier to justify (and explain).
$$ is etched into my fingertips; @@ is the fallback when I need to protect $1 and the like, typically for pic code that contains its own macros together with eqn constructs. ## has the virtue of not colliding with other eqn constructs or with groff macro definitions. It does collide with groff color specs and \# comments and with pic comments, so it's not a panacea, but seems better than $$. @@ may deserve consideration. The only collisions that come to mind are with the esoteric groff escape \$@.and with mentions of email addresses or shell scripts. Unfortunately, it is visually intrusive. You may also want to make a recommendation for delimiting bodies of eqn macros. I use %%--not perfect, but any conflicting groff constructs will be right there in full view. Doug
