feat(*): recreate library as scoped package

base/mf_mval.sas

@@ -0,0 +1,18 @@
+/**
+  @file mf_mval.sas
+  @brief Returns a macro variable value if the variable exists
+  @details Use this macro to avoid repetitive use of `%if %symexist(MACVAR) %then`
+  type logic.  
+  Usage:
+
+      %if %mf_mval(maynotexist)=itdid %then %do;
+
+  @version 9.2
+  @author Allan Bowe
+**/
+
+%macro mf_mval(var);
+  %if %symexist(&var) %then %do;
+    %superq(&var)
+  %end;
+%mend;