feat(*): recreate library as scoped package

base/mf_existvar.sas

@@ -0,0 +1,32 @@
+/**
+  @file
+  @brief Checks if a variable exists in a data set.
+  @details Returns 0 if the variable does NOT exist, and return the position of
+    the var if it does.
+    Usage:
+
+        %put %mf_existvar(work.someds, somevar)
+
+  @param libds (positional) - 2 part dataset or view reference
+  @param var (positional) - variable name
+  @version 9.2
+  @author Allan Bowe
+**/
+
+%macro mf_existvar(libds /* 2 part dataset name */
+      , var /* variable name */
+)/*/STORE SOURCE*/;
+
+  %local dsid rc;
+  %let dsid=%sysfunc(open(&libds,is));
+
+  %if &dsid=0 or %length(&var)=0 %then %do;
+    %put %sysfunc(sysmsg());
+      0
+  %end;
+  %else %do;
+      %sysfunc(varnum(&dsid,&var))
+      %let rc=%sysfunc(close(&dsid));
+  %end;
+
+%mend;