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From: elvy@harvard.ARPA (Marc Elvy)
Newsgroups: net.lang.c
Subject: Re: A Modest Extension to the C Preprocessor
Message-ID: <338@harvard.ARPA>
Date: Thu, 2-Aug-84 18:26:41 EDT
Article-I.D.: harvard.338
Posted: Thu Aug  2 18:26:41 1984
Date-Received: Sun, 5-Aug-84 05:05:20 EDT
References: <377@wdl1.UUCP>
Organization: Aiken Computation Lab, Harvard
Lines: 26

Actually, the #use suggestion sounds like a practical idea, but I doubt the
C "purists" will go for it.  Taking the suggestion one step farther, one
might use something like

	# require	DEFINITION	file

In case it is not obvious, this would act as follows:  If DEFINITION is
already defined, then the statement could be ignored; if DEFINITION is
not defined, then "file" would be #included.  This would, I suppose, take
the place of all the

	# ifndef	DEFINITION
	# include	file
	# endif		DEFINITION

sequences which are probably around.  Something like this would certainly
make my life a lot happier, since I am constantly having fights about
whether .h files should depend upon other .h files already being #included.
Incidentally, this is not my idea, per se -- the (require) function exists
in at least one Lisp system (T) and probably several others.

Marc

		      Marc A. Elvy  ( elvy@harvard.{arpa,uucp} )
			     Aiken Computation Laboratory
				  Harvard University