Newsgroups: comp.lang.lisp
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From: simon@rheged.dircon.co.uk (Simon Brooke)
Subject: Re: Why do people like C? (Was: Comparison: Beta - Lisp)
In-Reply-To: jeff@festival.ed.ac.uk's message of Fri, 7 Oct 1994 19:52:35 GMT
Message-ID: <CxMo10.514@rheged.dircon.co.uk>
Organization: none. Disorganization: total.
References: <36p4rb$6gd@relay.tor.hookup.net> <Cx5vqF.5E3@cogsci.ed.ac.uk> <36ui4a$3k2@relay.tor.hookup.net> <CxBJ7o.9Kv@festival.ed.ac.uk>
Date: Thu, 13 Oct 1994 20:10:10 GMT
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This thread has been rumbling on for some time, and the longer it
rumbles the more it bothers me. In it, various people (Jeff Dalton,
Bob Hutchinson, and the implausibly named Cyber Surfer amongst others)
have been arguing about whether C is easier to learn than LisP because
it more closely models hardware. Guys, what's hardware?

Xerox used to have a chip (it was never marketed, I think) which did
selector-method resolution (working out which method of which class is
being referred to in a message passed to an object) in one machine
instruction -- no, I do not jest. People can build in hardware any
unit of logic that we programmers use sufficiently frequently. Part of
the art of carving silicon is judging which operations are
sufficiently general to be made part of the sculpture, rather than
part of the song. 

OK, so now we have a silicon aesthetic which says we don't carve out
any piece of logic we can't evaluate in a single tick of the clock,
but that's a fashion. It ain't graven in stone.  Likewise, I once
spent a bored couple of days while recovering from 'flu working out
how you could build a LisP interpreter using only clockwork components
(rods, levers, cams and cogs).

The only difference between hardware and software is that software
works by logic, and consequently one can understand it. Hardware works
by improbable and unlikely things like quantum mechanics and electron
tunneling, and anyone who understands that hasn't got *time* for a life.

-- 
simon@rheged.dircon.co.uk

			-- mens vacua in medio vacuo --
