Date: Thu, 29 Feb 1996 10:36:52 -0500
Reply-To: Phil Gallagher <pgallagh@MAIL.CATO.COM>
Sender: "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From: Phil Gallagher <pgallagh@MAIL.CATO.COM>
Organization: Cato Research Ltd.
Subject: Thanks, re: macro parameter lists
Many thanks to everyone who wrote with respect to my query about style
aspects of writing macros with and without parameter lists. For some
time now I have been slavishly following the well known examples in
Michael Friendly's code and Ian Whitlock's code and (well-known, at least
to me) Karsten Self's code, using keyword parameter lists for macros.
And I had not really thought about why it was or was not a good idea - if
Michael and Ian and Karsten do it conscientiously, who am I to just go
off and do it some other way for no reason at all? Now I sit back and
can see what a mess one can get into with global macrovars created via
%LET stmnts, when all that is needed are local macrovars, and I'm very
glad that I've been taught how to do it correctly via the Masters'
Admittedly, my macros have been simpler than theirs, and I ought not
to have gotten into serious trouble anyway, but I urge all beginners to
look at Michael Friendly's statistical graphics macros (either buy his
book or find his examples in the archives) for good examples of keyword
parameter list style to emulate. It's easy for a beginner to just follow
the introductory examples in the SAS Guide to Macro Processing, where
they do use %LET to change values in a macro, but that's because they are
trying to keep the complexity of the introductory pages to a minimum; a
much better idea is to continue reading and master the (slightly) more
complex material which follows. If one wants, one can even try to master
the appreciably more complex matters that follow that, and get into the
discussions with Paul and Ian and John and Karsten of when things are
resolved! ;-) Shame on me!