Hi Wim, Roff syntax permits certain ASCII control characters in identifiers. They're typically used by older macro-packages to avoid naming conflicts, or in contexts when an arbitrary delimiter may appear in legitimate texts (such as the .tl request).
Acceptable control characters are: - ^B STX (Start of text) - ^C ETX (End of text) - ^E ENQ (Enquiry) - ^F ACK (Acknowledge) - ^G BEL (Alarm / bell) - ^? DEL (Delete) Groff also accepts ^D (End of transmission) and form feeds, although the latter might be unintentional. For full details on compatibility, see https://gist.github.com/Alhadis/b3931ccde8390de8c685bcc582a7060d#file-readme-md (This page excludes details for mandoc(1), as its syntax deviates from traditional Troff implementations w.r.t. valid identifier characters. I told Ingo about the discrepancy, but he seems reluctant to fix it). Cheers, — John On Tue, 2 Feb 2021 at 20:23, Wim Stockman <wim.stock...@gmail.com> wrote: > What is the purpose of this? ^G , control character. > I see it a lot used in the hdtbl macro set. > > Kind regards > Wim Stockman >