Path: utzoo!attcan!uunet!husc6!cmcl2!rutgers!tut.cis.ohio-state.edu!osu-cis!att!ihlpb!nevin1
From: nevin1@ihlpb.ATT.COM (Liber)
Newsgroups: comp.lang.misc
Subject: Re: colon-equal vs equal
Keywords: Oh no not again! :-)
Message-ID: <9282@ihlpb.ATT.COM>
Date: 28 Dec 88 01:29:47 GMT
References: <3300001@uxg.cso.uiuc.edu> <3290002@hpctdls.HP.COM>
Reply-To: nevin1@ihlpb.UUCP (55528-Liber,N.J.)
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 26

In article <3290002@hpctdls.HP.COM> rbk@hpctdls.HP.COM (Richard Katz) writes:

>I don't know how the := came into being, but I don't have any beef
>about it.  In fact, I think Pascal use of it is good.  Pascal uses =
>as a boolean operator and := as asignment.  First, := seems better
>since  i = i + 1 looks real funny.

It looks funny to me, too.  I much prefer "i += 1", but I don't remember
augmented assignment being legal in Pascal.

>Also, a nice feature is that
>'if ( i := 10 )' will produce a syntax error in Pascal while
>'if ( i =  10 )' will produce an assignment in C, usually not
>intended.

This really has nothing to do with ":=" vs "=".  C is an
expression-based language; Pascal is not (by expression-based I mean
that every operator returns a value that can be used as one of the
parameters for another operator).  In Pascal, just about (ie, I'm not
100% sure :-)) every use of ":=" could be replaced by "=" with no
ambiguities arising (please don't flame me if there is an exception to
this statement; it would not be difficult to change the language so that
none of these ambiguities arise).  Heck, even my TRS-80 Model I Level II
BASIC could differentiate between these two cases! :-)
-- 
NEVIN ":-)" LIBER  AT&T Bell Laboratories  nevin1@ihlpb.ATT.COM  (312) 979-4751