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From: josh@topaz.ARPA (J Storrs Hall)
Newsgroups: net.lang
Subject: Re: levelheight
Message-ID: <354@topaz.ARPA>
Date: Mon, 21-Jan-85 21:25:11 EST
Article-I.D.: topaz.354
Posted: Mon Jan 21 21:25:11 1985
Date-Received: Wed, 23-Jan-85 06:08:32 EST
References: <2340@hplabsc.UUCP> <4948@utzoo.UUCP> <6292@boring.UUCP>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 37

> 
> > I wonder whether this is widespread. The problem with safety devices
> > is that people rely on them to do their thinking for them in situations
> > where they shouldn't.
> I don't think this is a property of safety devices. I don't get the
> impression that people drive worse if they're wearing a safety belt, for
> instance.

I sure as hell do.  And I know many people who do, but wouldn't admit it.

Let me opine that there are *three* different approaches to this
high-levelness/typing morass (at least...).  Let me try to show how
they apply to, say, numbers:

1) Assembly style:  The "language" doesn't know about objects, just
operations.  You must keep track of the "type" of each location in
your head.  (For this reason, good assy. language programmers tend
to have very large heads :^)

2) Pascal style:  The language knows about all the types and keeps
strict track of them to let you know when you make a mistake.
Essentially the compiler works as an automated cribsheet to help you
keep track of the mass of detail you had to keep in your head before.

3) APL style:  The language presents the single concept "number"
to the programmer, who never has to worry about the implementation
thereof.  The programmer never even knows whether that number was
actually represented as a bit, integer, float, whatever.  The 
machinery of the system does all the worrying.

Disclaimer:  I do not claim to defend all the odd customs and mores
of APL, but advance this concept as an example.

Styles 2 and 3 have the common problem that the implementation
is restrictive; that is, the implementor (designer) must have had
in mind the kind of thing you are trying to do, or you can't
do it.