Date:         Mon, 23 Feb 2004 16:15:11 -0500
Reply-To:     Quentin McMullen <quentin_mcmullen@BROWN.EDU>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Quentin McMullen <quentin_mcmullen@BROWN.EDU>
Subject:      macro parameter foolishness

Hi All,

Having spent many too many minutes trying to debug a bizarre macro mess I
accidentally made for myself, I thought I would share.

Here is my mess in the form of a puzzle:

%macro me(/*fill me in*/);
  %put a=&a;
%mend me;

What can you put into /*fill me in*/ so that the macro call %me(a=1) will
return:
a=


Answer below:

Might have hoped that defining a macro with >1 parameter with the same
name might create an error, or perhaps note?  But no, SAS chugs along
happily, with sometimes surprising results:

22523  %macro me(a=,a=);
22524    %put a=&a;
22525  %mend me;
22526
22527  %me(a=1)
a=

Kind Regards,
--Quentin