feat: new macro to determine if a macro variable value is an integer - mf_isint (and associated test)

base/mf_isint.sas

@@ -0,0 +1,33 @@
+/**
+  @file
+  @brief Returns 1 if the variable contains only digits 0-9, else 0
+  @details Note that numerics containing any punctuation (including decimals
+    or exponents) will be flagged zero.
+
+  If you'd like support for this, then do raise an issue (or even better, a
+  pull request!)
+
+  Usage:
+
+      %put %mf_isint(1) returns 1;
+      %put %mf_isint(1.1) returns 0;
+      %put %mf_isint(%str(1,1)) returns 0;
+
+  @param [in] arg input value to check
+
+  @version 9.2
+**/
+
+%macro mf_isint(arg
+)/*/STORE SOURCE*/;
+  /* remove minus sign if exists */
+
+  %local val;
+  %if "%substr(%str(&arg),1,1)"="-" %then %let val=%substr(%str(&arg),2);
+  %else %let val=&arg;
+
+  /* check remaining chars */
+  %if %sysfunc(findc(%str(&val),,kd)) %then %do;0%end;
+  %else %do;1%end;
+
+%mend mf_isint;