The groff language is a bit of a legacy UNIX program for generating post-script documents with graphics and all kinds of other handy text formatting. If you run it with the help option on macOS 12.5 Monterey, you're informed that it supports the following options:
usage: groff [-abceghijklpstvzCEGNRSUVXZ] [-dcs] [-ffam] [-mname] [-nnum]
[-olist] [-rcn] [-wname] [-Darg] [-Fdir] [-Idir] [-Karg] [-Larg]
[-Mdir] [-Parg] [-Tdev] [-Wname] [files...]
-h print this message
-v print version number
-e preprocess with eqn
-g preprocess with grn
-j preprocess with chem
-k preprocess with preconv
-p preprocess with pic
-s preprocess with soelim
-t preprocess with tbl
-G preprocess with grap # <--- here
-J preprocess with gideal
Unfortunately, it seems that as soon as the grap pre-processor is included, I'm greeted with the following:
% groff -G -p -Tpdf -mspdf grap.ms > grap.pdf
groff: couldn't exec grap: No such file or directory
Is the groff binary incomplete, or missing some extensions? Looking around turns up almost nothing other than some mailing list discussions from 2005. For what it's worth, other extensions like eqn and pic work alright.
