Date: Wed, 19 Sep 2001 09:53:58 -0700
Reply-To: Cassell.David@EPAMAIL.EPA.GOV
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: "David L. Cassell" <Cassell.David@EPAMAIL.EPA.GOV>
Subject: Re: SAS Comments
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John Whittington wrote:
> Roland, there I have to disagree with you. An unmatched quote within a
> *...; type of comment is no problem. After the asterisk, SAS treats
EVERY
> character it finds as being part of the comment until it hits the next
> semicolon - hence, it is perfectly safe to put ANYTHING in a *...; type
of
> comment EXCEPT for a semicolon.
I agree. But let me point out one analogue where this is an issue. An
unmatched quote inside a %*...; comment can wreak untold havoc. Unmatched
quotes inside these macro comments are picked out by the compiler, while
unmatched quotes inside *...; comments are not. I was badly bitten by this
just a couple months ago when I typed up a few paragraphs of documentation
inside a large macro and used a contraction without noticing. Ouch.
> As for the relative 'safety' of the two approaches, I again have to
> disagree with you. Like many other people I know, I virtually never use
> the /*...*/ type of comment, because of the serious potential hazard
caused
> by their 'un-nestability'. Rightly or wrongly, /*...*/ is often used to
> 'comment out' blocks of code during testing/development, and that can
> result in chaos if there are /*...*/ comments within the block of code in
> question.
A good point, but I have an alternative that I use instead.
I prefer to use the "%MACRO SKIP" routine. I find it is safer to block out
large chunks of code like this:
%MACRO SKIP;
the code I
wanted to block out
so it would not
be executed or even
examined by the
compiler...
%MEND SKIP;
It was recommended in SAS-L a long time ago, and is a nifty tool to keep
in one's bag o' tricks...
David
--
David Cassell, CSC
Cassell.David@epa.gov
Senior computing specialist
mathematical statistician
