Pass Character dynamically to a macro - sas

Question

I'm trying to pass file name to a macro. The macro runs once a month, therefore,I'm trying to store the output file with a month prefix. In the current code someone has to manually provide a file name every month (Sep17_Sales, Oct17_Sales etc.). I want to automate this so that SAS generates files with the name of the month prefixed to the data file.
Macro:
%macro sales (outdata = , dt =);
Current Code
%Sales(Outdata = Sep17_Sales, dt = '2017-09-01');
%Sales(Outdata =Oct17_Sales, dt ='2017-10-01');
My approach:
data _null_;
current_date = today();
current_month = intnx('month', current_date, 0, "Begginning");
Name = "_Sales";
Result = put(current_month, monyy7.) || name;
run;
%Sales(Outdata=Result, dt='2017-10-01');
When I try to pass the parameter, it throws error. I tried changing Result to %Let Result and pass a reference &Result to the macro but it also fails.
Any suggestion how to solve this? Thank you for all the help!!

Answer 1

What you are doing there is assigning a value to a data step variable called Result. The name Result doesn't mean anything outside the context of that datastep and therefore does not resolve to anything when you call your macro. What you are doing instead is telling your macro that your output file should be called "Result".
You could fix that by replacing your Result= line with call symput('Result',put(current_month, monyy7.) || name);, which effectively creates a macro variable called "Result", then call your sales macro like so: ``%Sales(Outdata=&Result, dt='2017-10-01');
OR, you could scratch all that and simply call your macro like this:
%sales(outdata=%sysfunc(today(),monyy7.)_Sales, dt='2017-10-01');
Going further, assuming the second argument (dt) is always meant to be the first day of the month formatted as yyyy-mm-dd and enclosed in single quotes (although if that is the case I see little use in specifying it as a parameter of the macro), you could make the call even more dynamic:
%sales(outdata=%sysfunc(today(),monyy7.)_Sales, dt=%str(%')%sysfunc(intnx(month,%sysfunc(today()),0,B),E8601DA.)%str(%'));
if that date can be enclosed in double quotes, this can be simplified a little as:
%sales(outdata=%sysfunc(today(),monyy7.)_Sales, dt="%sysfunc(intnx(month,%sysfunc(today()),0,B),E8601DA.)");