|Date: ||Thu, 22 Jun 2006 16:07:16 +0000|
|Reply-To: ||toby dunn <tobydunn@HOTMAIL.COM>|
|Sender: ||"SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>|
|From: ||toby dunn <tobydunn@HOTMAIL.COM>|
|Subject: ||Re: macro structure|
|Content-Type: ||text/plain; format=flowed|
Opps hit the send button too fast. From a design stand point the second
example could said to be perfectly coupled. Which isnt what you want.
"So what did Michelangelo do when planning to paint the Sistine Chapel? The
same thing you should do when faced with a big task.
Michelangelo divided his mural into panels: separate, free-standing areas,
each of which tells a story. But he did so fairly carefully, such that the
panels exhibit these characteristics:
These are things we can learn from
Michelangelo's panels have low coupling; they are all self-contained; there
are no instances of figures reaching from one panel into the next, for
instance. Why is that important?
If you look closely at one of the panels that portrays angels gliding about
the firmament of heaven, you'll notice that one of the angels is turning his
back to, and gliding away from, the other angels. You'll also notice that
said angel isn't wearing any pants. He's rather pointedly "mooning" the
There is surely a tale that explains the bare tail of the mooning angel, but
for now let's assume that the Pope discovered the mooning angel and demanded
that it be replaced. If the panels weren't independent, then the replacement
of one panel would entail replacing some adjacent panels as well—and if you
had to use different pigments because the originals weren't available, maybe
you have to replace the next set of panels that were indirectly affected.
Let the nightmare begin. But as it stands, the panels are independent, so
the offending angel (who was apparently on Spring Break) could have been
easily replaced with a less caustic image and the rest of the project would
From The Art in Computer Programming
By Andrew Hunt and David Thomas
From: Ya Huang <ya.huang@AMYLIN.COM>
Reply-To: Ya Huang <ya.huang@AMYLIN.COM>
Subject: macro structure
Date: Thu, 22 Jun 2006 11:52:59 -0400
%do i=1 %to &xx;
%do i=1 %to &xx;
So for structure 1, two macro are separated in two files, %main
can call %a because of the auto macro call library.
For structure 2, %a is defined inside %main, but before the looping.
Is there significant benifit of 1 over 2?