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From: franka@mmintl.UUCP (Frank Adams)
Newsgroups: net.lang
Subject: Re: Multiple assignments
Message-ID: <1482@mmintl.UUCP>
Date: Tue, 20-May-86 18:32:04 EDT
Article-I.D.: mmintl.1482
Posted: Tue May 20 18:32:04 1986
Date-Received: Fri, 23-May-86 23:55:52 EDT
References: <1455@mmintl.UUCP> <825@bentley.UUCP>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Multimate International, E. Hartford, CT
Lines: 21

In article <825@bentley.UUCP> kwh@bentley.UUCP writes:
>In article <1455@mmintl.UUCP> franka@mmintl.UUCP (Frank Adams) writes:
>>... Supposing that "$" is being used for this ["multi-assignment"] operator,
>>then to set both "a" and "b" to zero, one would write "a $ b = 0", rather
>>than "a = b = 0", as C does....  
>>On the other hand, if your language supports argument passing by address,
>>it permits an output argument to be multiply assigned; something which
>>assignment-with-value does not support.
>
>What do you mean by this?  I don't see how this operator allows you to do
>anything that simple assignment doesn't.  Examples?

Well, in C it doesn't, since C supports call by value only.  In PL/I, for
example, one could write a procedure (called, say, getlin) which would read
a line from a file; it has four parameters -- a file, a buffer, the length
of that buffer, and the number of characters read.  With a "$" operator, one
could then write something like "getlin(fp, buff, buflen, actlen$lenread);";
without it, one must use a separate assignment.

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Multimate International    52 Oakland Ave North    E. Hartford, CT 06108