[TUHS] pic macros

[Warren Toomey via TUHS]

-------- Original Message --------
From: "G. Branden Robinson" <g.branden.robinson at gmail.com>
Sent: 8 January 2026 7:14:38 am AEST
To: tuhs at tuhs.org
Cc: wkt at tuhs.org
Subject: Re: [TUHS] Re: pic macros

[CCing Warren so he can forward if necessary; as far as I know the
Gmail->TUHS relationship is still sour, at least for me]

At 2026-01-07T15:19:13-0500, Clem Cole via TUHS wrote:
> On Wed, Jan 7, 2026 at 1:53 PM Douglas McIlroy via TUHS <tuhs at tuhs.org>
> wrote:
> > I haven't found pic in the TUHS v7 source tree. Does anyone have a
> > running version of it?
> >
> That's because it was not released in V7.

As someone who definitely Wasn't There but has done a little research,
I'd venture that pic wasn't yet _finished_ in time for V7.

CSTR #97, "A Typesetter-Independent TROFF", by Kernighan, documents the
process of creating same.  See §7, "Graphics Commands", where he
introduces the `\D` troff escape sequence upon which pic relies as a
translation target.  Writing in 1982, Kernighan says:

"Since actual output is done by a post-processor, not TROFF, new
capabilities for graphics have been easy to add.  TROFF now recognizes
commands for drawing diagonal lines, circles, ellipses, circular arcs,
and quadratic B-splines; these are used in the PIC[...] and IDEAL[...]
languages." (p. 2; PS/PDF p. 4)

> (ditroff was part of the later "toolchest" ditroff distributions; it
> might have been part of the original ditroff for the v6/v7 release
> that included the new C compiler)

If I understand the history correctly, it would certainly have had to
have been backported to those Unices; V7 is dated 1979, and Kernighan
reports his work on what came to be known as "ditroff" in "early 1979"
per CSTR #97.

Regards,
Branden

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