Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!chinacat!sequoia!rpp386!jfh
From: jfh@rpp386.cactus.org (John F Haugh II)
Newsgroups: comp.sources.d
Subject: Re: Help define Environment: usage in c.s.m
Message-ID: <19379@rpp386.cactus.org>
Date: 12 Jun 91 14:55:48 GMT
References: <1991May26.041741.22210@sparky.IMD.Sterling.COM> <20585:Jun1203:03:5491@kramden.acf.nyu.edu>
Organization: River Parishes Programming, Austin TX
Lines: 48

In article <20585:Jun1203:03:5491@kramden.acf.nyu.edu>, brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes:
> > Whereas if just about any POSIX compliant UNIX with BSD enhancements
> > is likely to work, it would be
> > 	Environment: POSIX && BSD
> 
> Again, the point of this line is for people (not your C compiler---what's
> this && stuff?) to avoid bothering with a package that they can't use. It
> should read like a set of danger signs:
 
Gee, I don't know Dan, What's the deal with the "!"s and "<", ">", and
"="'s in yours?

>    Wont-Work-With: non-POSIX, non-BSD

Which is the same as

Works-With: POSIX Compliant BSD Systems.

I won't try to make this argument using the linguistic point that many
non-English languages have trouble with the English concept of negation,
as it exists in English.  That would be cheating, since it would point
to a non-computer related reason that unneeded negation of the sense of
the information is confusing.  Instead I'll point out how silly a double
negative looks in English, which before was how silly a double negative
looked in computerese ...

The set of environments that the software is likley to execute on is
far smaller than the set of environment that it will execute on.  [ There
are simply too many weird environments, like "Won't run on an HP-41
handheld programmable calculator", to name every incompatible platform
using non-negated language.  That is, if it runs on UNIX and VMS, the
set of other operating systems is best described as "not UNIX and not
VMS", rather than "RT/11, RSTS, RSX, TENEX, TWENIX, ..." [ and those
were just the popular DEC O/S's - ignore the popular IBM ones for the
time being ... ]  Since the set of all known operating system is quite
large, your scheme practically requires that every specification be
given as "not this system, not that system, not some other system",
rather than just dragging all the not's out and getting rid of that
"Wont-" at the beginning.  Now it is "this system, that system, some
other system".  Which does, coincidentally, have the linguistic
property of being simplier to understand.  And it doesn't contain a
single double negative either.  [ Or in Dan-ese "Doesn't contain not
none double negatives." ]
-- 
John F. Haugh II        | Distribution to  | UUCP: ...!cs.utexas.edu!rpp386!jfh
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