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From: see@NTA-VAX.ARPA
Newsgroups: net.lang.c
Subject: define kinda stuff
Message-ID: <2602@brl-smoke.ARPA>
Date: Mon, 14-Apr-86 03:02:33 EST
Article-I.D.: brl-smok.2602
Posted: Mon Apr 14 03:02:33 1986
Date-Received: Sun, 20-Apr-86 18:09:05 EST
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David Eppstein (eppstein@cs.columbia.edu, seismo!columbia!cs!eppstein)
writes (11 Apr 86 21:12:26 GMT)

> Obviously the right way to do this is the following:
> 
> 	#define  cat(a,b)  a/**/b
> 	#define  (-:       cat(/,*)
> 	#define  :-)       cat(*,/)

The problem is to define '(-:' as '/*' (start of comment), and :-) '*/'.

Please correct me, but I feel this will not work. Either the cat-definition
will look like 'ab' when it is expanded - obviously wrong -, or it will
look like 'a/**/b', which is wrong also. If you get '//**/*' as the
expansion, this surely isn't a start of a comment. 

The whole thing boils down to whether the preprocessor does recursive 
deletion of comments, which it never has as far as I know. For example:

/*	if (variable != 21) { 		/* Test for ... */

has always been a comment-line, where the first '/*' is an easy
way to discard the whole line. If you put another '*/' at the end of
the line, the 'syntax error' is very near...