Date:         Thu, 20 May 2010 10:31:50 -0400
Reply-To:     "W. Matthew Wilson" <matt@TPLUS1.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "W. Matthew Wilson" <matt@TPLUS1.COM>
Subject:      Tools to visualize dataset dependencies?
Content-Type: text/plain; charset=ISO-8859-1

I inherited some REALLY long SAS programs that use lots and lots of
data steps and I'm having a hard time keeping it all in my brain.

I'm a big fan of dot (http://graphviz.org) and I would like to use it
to graph the dependencies.  Has anyone done anything like this?

For example, I want to translate the SAS code below:

    data b;
        set a;
        /* skip lots of variable assignments here */
    run;

    proc summary data=b;
        /* skip various options here */
        output out=c;
    run;

    data e;
        merge c d;
    run;

Into something like this dot syntax:


    digraph G {
        a -> b [label="data step"];
        b -> c [label="proc summary"];
        c -> e [label="data step"];
        d -> e [label="data step"];
};

And then dot will make a purty picture, like this one
:http://scratch.tplus1.com/scratch.png

When I look at that picture, it is obvious to me that the two input
datasets that must already exist for this code are a and d.  That fact
is NOT obvious when I read the code, especially since I really have >
50 intermediate data steps in this program and at least a dozen
prerequisite datasets.

Is there already a tool to visualize dependencies like this?  Does
anyone have any other ideas for how to attack this problem?

Thanks in advance.

--
W. Matthew Wilson
http://tplus1.com