Oh, I'm not arguing with any of this. I'm merely noting that
you are unusual in your ability to easily visualize pic results
from looking at the code.
Arnold
Larry McVoy <
lm@mcvoy.com> wrote:
Well, I stand behind my comments. Take a look at what xfig(1)
produces and contrast that with even an average pic(1) source
file. You can't see what xfig is saying but you can easily see
what pic is saying.
Maybe people just haven't written much pic, but what you can do
with it, and see without rendering it, is pretty amazing.
I got James Clark to add the 'i'th concept so you could do for
loops to lay out elements and I wrote a pic script where you
could set variables like cpus, networks, disks and it would
draw different configurations of a SPARCcluster.
Pic is pretty neat, I find it easier to read than any of the
other troff preprocessors.
On Wed, Aug 10, 2022 at 09:05:20AM -0600, arnold@skeeve.com wrote:
Hi All.
Douglas McIlroy <douglas.mcilroy@dartmouth.edu> wrote:
I've always believed that pic was so well designed
because it took a day to get the print out (back then),
I'm afraid this belief is urban legend. Credit for pic is due 100% to
Kernighan, not to the contemporary pace of computing practice.
I occassionally forward TUHS items (that I think are) of interest
to Brian. I have in the past forwarded one of Larry's "I like pic
because I can read the code and visualize the picture" emails to
him. He responded that he didn't work that way. :-)
Here, by permission, is his response to Larry's latest note of
that kind, which I think is also of more or less general interest:
Date: Tue, 9 Aug 2022 19:03:00 -0400 (EDT)
From: Brian Kernighan <bwk@cs.princeton.edu>
To: arnold@skeeve.com
Subject: Re: larry mcvoy on pic, again
I don't know that I would read too much into the development of
Pic, though my memory is so dim that it would all be made up
anyway.
One observation: with Yacc and Lex available, languages were a lot
easier to implement; I had already done a troff preprocessor so
that aspect was well in hand. And I was actually the owner of
troff at the same time, so I could mix and match (e.g., the
primitives for drawing lines). I think that "seeing the output"
wasn't too hard, either because I could use the typesetter, or the
Tectronix 4014 (?) for which there was a troff output emulator
that I think I wrote.
The main issues as I recall were figuring out coordinate systems,
since Pic had Y going positive as with conventional plotting,
while troff had it going negative (down the page is higher Y
values).
But it's all kind of fuzzy at this point.
--
---
Larry McVoy Retired to fishing http://www.mcvoy.com/lm/boat