On Fri, 21 Jul 2023 22:33:09 -0500
Nate Bargmann <n...@n0nb.us> wrote:
> Looking at the railroad diagram, I wonder if there are enough drawing
> characters in UTF-8 that they could be used for the diagrams rather
> than generating image files that would likely not be useful for
> terminal output.
Thanks for reminding me, Nate. Here's a current result:
$ groff -T utf8 -mandoc -pet ./gcobol-start.3c
GCOBOL-START(3c) GCC COBOL
GCOBOL-START(3c)
NAME
START position file for reading
SYNOPSIS
???????? ?????????
??????START??????filename?????????????????????????
????????
???????FIRST???????????????????????????????????????
????????????????????????????????????????????
? ??LAST?? ????????? ?????????
?????? KEY ???????????compare?????? name ??
??????????????? operator? ???????
?? IS ??
???????
???????????????????????????????????????????????????
? ??????? ?LENGTH????expr???
??????WITH ??
????????
???????????????????????????????????????????????????
???????????????????????????????????
INVALID????????error-statements
? KEY ?
????????
????????????????????????????????????????????????????????
?????? NOT ?????????????????????????????????????
INVALID????????valid-statements?END-START??
? KEY ?
????????
I haven't tried to understand exactly what's going on with that. pic
is emitting troff input, and troff, I expect, is emitting drawing
instructions in ditroff, which grotty renders. Something is evidently
lost in translation.
The grotty manual mentions, under BUGS:
"There is no support for \D commands other than horizontal and
vertical lines."
Given that constraint, a useful rendering might be possible if the pic
input took care to align the boxes and lines consistent with grotty's
character matrix.
But, how? An xterm determines its own font; it doesn't not
respond to in-band font requests. And there is no way afaik for a troff
drawing instruction to say "line right 7 characters; line down 3
lines", using whatever sizes the terminal decided on.
That leaves us standing before my favorite hobbyhorse. The demise of
Display Postscript doomed the possibility of a Unix graphical
terminal. We had X, so applications could draw, but nothing like
"printing to the screen", where a data stream could control a graphical
terminal akin to how a data stream controls a graphical printer.
Instead, we got HTML, and thence epub.
What would you use your MacArthur grant for? I know what I would do: I
would create VT-roff, an xterm that, instead of recognizing VT-100
control codes, would recognize ditroff(5) output. Then we could have
manpages "in the terminal" as good as on paper, or a PDF.
--jkl
