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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
Content-type: text/plain; charset=us-ascii

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


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