Hi John, John Gardner wrote on Sun, Nov 20, 2016 at 02:27:43AM +1100:
> Regarding HTML... I fully hear what you're saying. Somebody asked for a > realtime preview of manual-page editing > <https://github.com/Alhadis/language-roff/issues/3> for Atom (a text editor > which is built using web technologies: HTML, CSS, JavaScript, etc). I > thought it'd be simple to implement in barebones HTML, but quickly realised > what I was getting myself into. > > So I've decided to use HTML5 <canvas> instead, piping Groff's intermediate > output through a separate process and lexing the instructions to plot basic > drawing operations in a side pane. Heck of a lot simpler than translating > HTML to/from *Roff... =) For that particular task, you may want to consider using mandoc(1) -Thtml rather than groff, see http://mdocml.bsd.lv/ . Even though groff (Postscript, PDF, ...) typesetting abilities are far superior to mandoc and mandoc is limited to the mdoc(7), man(7), tbl(1), and eqn(1) languages, mandoc HTML output for manual pages may be better than groff output, see http://man.openbsd.org/ for examples. You certainly don't need any lexing, mandoc generates polyglot HTML5 out of the box. Mandoc HTML output contains many semantic class="..." annotations, so you can easily customize it with CSS. For HTML output of manual pages, mandoc may be up to two orders of magnitude faster than groff: schwarze@isnote $ time groff -mdoc -Thtml ksh.1 > /dev/null 0m02.58s real 0m02.72s user 0m00.09s system schwarze@isnote $ time mandoc -mdoc -Thtml ksh.1 > /dev/null 0m00.03s real 0m00.03s user 0m00.00s system schwarze@isnote $ time groff -man -Thtml perltoc.1 > /dev/null 0m08.86s real 0m09.18s user 0m00.30s system schwarze@isnote $ time mandoc -man -Thtml perltoc.1 > /dev/null 0m00.21s real 0m00.19s user 0m00.02s system schwarze@isnote $ time groff -man -Thtml bash.1 > /dev/null 0m04.23s real 0m04.38s user 0m00.14s system schwarze@isnote $ time mandoc -man -Thtml bash.1 > /dev/null 0m00.04s real 0m00.03s user 0m00.02s system That may matter for repeated processing, in particular on a web server. Finally, from a security perspective, groff may not be quite ideal for running on a web server; it is relatively old, not quite security- centric code, while mandoc has been exhaustively tested with the afl(1) fuzzer and in addition to that, the HTML output module got a complete manual security review by Sebastien Marie. Yours, Ingo
