Ralph, Thank you for this valuable advice. I will try to use it, especially and hopefully for exploring the internal workings of some macro sets like pdfmark.
Piotr Ralph Corderoy <ra...@inputplus.co.uk> wrote .. > Hi Piotr, > > Tadziu wrote: > > > I quess that groff -R automatically activates refer.tmac and all > > > registers like [F become available. Correct? > > > > No, -R only filters the input document through the "refer" > > preprocessor before processing it with the actual formatter "troff". > > See groff(1)'s -V option to better understand what's happening. In a > way, groff just obscures the workings for convenience, and I'm not sure > that's a good idea. It may be better to avoid it and use the underlying > commands whilst you're learning. > > $ groff -V /dev/null > troff -Tps /dev/null | grops > $ groff -V -R /dev/null > refer /dev/null | troff -Tps | grops > > > For example, troff.org lists M. E. Lesk's "Some Applications of > > Inverted Indexes on the UNIX System" as providing a basic overview of > > how refer works. > > https://troff.org/papers.html#refer > > -- > Cheers, Ralph.