Path: utzoo!mnetor!uunet!husc6!cca!g-rh
From: g-rh@cca.CCA.COM (Richard Harter)
Newsgroups: comp.lang.c
Subject: Re: { initializer-list , }
Message-ID: <25526@cca.CCA.COM>
Date: 14 Mar 88 05:44:19 GMT
References: <660@kuling.UUCP>
Reply-To: g-rh@CCA.CCA.COM.UUCP (Richard Harter)
Organization: Computer Corp. of America, Cambridge, MA
Lines: 31

In article <660@kuling.UUCP> bjornc@kuling.UUCP (Bj|rn Carlsson) writes:
>Why is an optional trailing comma inside the braces after an initializer-list
>allowed? Since it doesn't affect the meaning of the initializer we can't
>see any other reasons for including it except historical. Is it included
>in the Draft proposed ANSI C? We are currently writing a compiler for a
>subset of C and got a bit confused when finding this strange syntax.
>It is documented in both K&R and Harbison&Steele (2nd ed.).

This is one of those little things that makes life a little nicer for
people who have to maintain code.  Suppose you have a table of records,
with one item per line, all nicely aligned in columns for readibility.
Suppose you want to add a new record; you may enter a new record with
out altering the line for the old record -- your code control rev history
will be cleaner.  Again, suppose that your table of initializers is machine
generated;  the generator code will be simpler if the last item is not a
special case.  Indeed, if you think about it, the specification is simpler
if the comma is a terminator rather than a separator because all items in
the specification list have the same format, instead of the last one having
a special format.

C's use of the semicolon is analogous; C uses a semicolon as a statement
termninator rather than as a separator as in Algol and Pascal.  In that
case human factors studies have found that the C treatment is superior
to the Algol treatment -- fewer semicolon errors are made when the C
style is used than when the Algol style is used.  

-- 

In the fields of Hell where the grass grows high
Are the graves of dreams allowed to die.
	Richard Harter, SMDS  Inc.