arnold at skeeve.com arnold at skeeve.com
Thu Aug 11 01:05:20 AEST 2022

Hi All.

Douglas McIlroy <douglas.mcilroy at 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 at cs.princeton.edu>
> To: arnold at 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.

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