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From: allbery@ncoast.UUCP (Brandon Allbery)
Newsgroups: net.unix-wizards,net.bugs.4bsd
Subject: csh variables
Message-ID: <1086@ncoast.UUCP>
Date: Mon, 31-Mar-86 19:43:08 EST
Article-I.D.: ncoast.1086
Posted: Mon Mar 31 19:43:08 1986
Date-Received: Wed, 2-Apr-86 07:42:06 EST
References: <676@nbires.UUCP> <2021@hao.UUCP> <678@nbires.UUCP>
Reply-To: allbery@ncoast.UUCP (Brandon Allbery)
Followup-To: net.unix-wizards
Distribution: net
Organization: North Coast Computer Resources
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Xref: linus net.unix-wizards:14491 net.bugs.4bsd:1713

Expires:

Quoted from <678@nbires.UUCP> ["Re: C-Shell weirdness (count of words in a variable)"], by nose@nbires.UUCP (Steve Dunn)...
+---------------
| > 
| > > 2: Count of number of words in a variable (Or when is nothing something)
| > > 
| > > This:
| > > 
| > > set hosed = ''
| > > echo $#hosed
| > > 
| > > yields the result '1'
| > 
| >   But of course! The variable has one value: a null string. And, if you do
| > 
| > set hosed=( '' junk)
| > 
| > then what do you suppose $#hosed is? If you got 2, drink a potion of raise
| > level and read on! :-) If you do
+---------------

I had a flash of insight one day after trying unsuccessfully to figure this
out; think of it not as Bourne shell variables, but as an obscure dialect of
LISP.  If '' is T and () is NIL then the behavior of

	set foo

versus

	set foo = ()

is reasonable.  It also explains the word business reasonably.  (I'm thinking
specifically of a very limited LISP I ran into once; I don't remember which
one, but it had never heard of dotted pairs  Maybe it was based on csh :-)

--Brandon
-- 
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