Overiding a local macro when program is called

[texasmfp]

I have a macro variable defined inside a program (program1) for a fudge factor.

%LET fudge = 1.00;

When I run that program as a standalone, I want it to remain at 1.00.

However, I have another program (program2) that calls up and runs program1 several times; each time replacing the value of fudge factor. 

%LET fudge 	= 1.01;				/* Total number in subset */
%include "&PATH\&hmprog";
%include "&PATH\&usprog";

%LET fudge 	= 1.02;				/* Total number in subset */
%include "&PATH\&hmprog";
%include "&PATH\&usprog";

%LET fudge 	= 1.03;				/* Total number in subset */
%include "&PATH\&hmprog";
%include "&PATH\&usprog";

%LET fudge 	= 1.04;				/* Total number in subset */
%include "&PATH\&hmprog";
%include "&PATH\&usprog";

%LET fudge 	= 1.05;				/* Total number in subset */
%include "&PATH\&hmprog";
%include "&PATH\&usprog";

While I can manually edit the called program1 to delete the "%LET fudge = 1.00;" line and resave, I was hoping there was a way to avoid that.  That is, to have the macro variable's value in program2 override the 1.00 value in program1 without having to manually edit that line out and resave (and then reverse it when I want to run program1 as a standalone).

Thanks

[Patrick · Accepted solution]

You could use code as below in your program1 to only create and populate macro variable &fudge if it doesn't exist already.

data _null_;
  if not symexist("fudge") then 
    do;
      call symputx('fudge','1.00');
    end;
    stop;
run;

[texasmfp]

Thanks. I love SAS Communities!!!