Larry McVoy lm at mcvoy.com
Thu Aug 11 03:14:17 AEST 2022

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 at skeeve.com wrote:
> 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.

Larry McVoy           Retired to fishing          http://www.mcvoy.com/lm/boat

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