10 Aug
2022
10 Aug
'22
9:05 p.m.
Hi All.
Douglas McIlroy <douglas.mcilroy(a)dartmouth.edu> wrote:
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:
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. Date: Tue, 9 Aug 2022 19:03:00 -0400 (EDT)
From: Brian Kernighan <bwk(a)cs.princeton.edu>
To: arnold(a)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.