groff

Groff is the GNU replacement for the troff and nroff text formatters. It is an original implementation written primarily in C++ by James Clark and is modeled after ditroff, including many extensions. Groff contains a large number of helper programs, preprocessors, and postprocessors including eqn, tbl, pic and soelim. There are also several macro packages included that duplicate, expand on the capabilities of, or outright replace the standard troff macro packages.