Date:         Sat, 31 Mar 2007 18:14:55 -0500
Reply-To:     "Richard A. DeVenezia" <rdevenezia@WILDBLUE.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Richard A. DeVenezia" <rdevenezia@WILDBLUE.NET>
Subject:      Re: code challenge: subroutine checks that caller has %local
              mvars to
Comments: To: sas-l@uga.edu

Martin Gregory wrote:

> It looks like sashelp.vmacro is treated like a stack: if you could
> rely on that, then you'd know what the calling macro is.

Thediscovery process that supplies the DICTIONARY.MACRO view certainly does
appear to deliver information in a stack.  But there is no indication of the
call stack, which obviously must be known to the macro supervisor.  See
option MPRINTNEST.

Without documentation stating the view is a stack, I would argue against
building a macro library on the potential sandpit it will not be in the
future.

Sample of a recursive macro:
--------------------------------------------
%macro recurse (n=1);

  %if &n > 10 %then %return;

  %local MyMacroVar ;

  %let MyMacroVar = %sysevalf(&n**2);

  title "recurse called with n=&n";

  proc print data=sashelp.vmacro;
    where name like 'MY%';
  run;

  %recurse (n=%eval(&n+1))
%mend;

options ;

%put %sysfunc(pathname(work));

ods listing close;
ods html file="%sysfunc(pathname(work))\recurse-report.html" style=meadow;

%let myMacroVar = CornerStone;
%recurse;

%symdel myMacroVar;

ods html close;
--------------------------------------------

--
Richard A. DeVenezia
http://www.devenezia.com/