diff --git a/PermutationOf.sas b/PermutationOf.sas
new file mode 100644
index 0000000..cc0ac37
--- /dev/null
+++ b/PermutationOf.sas
@@ -0,0 +1,66 @@
+/*
+by Jian Dai
+https://www.clinovo.com/userfiles/PharmaSug-SAS-Macros-for-List-Permutations.pdf
+
+*/
+
+%macro TheFirstWordOf(List=);
+	%scan(&List,1)
+%mend;
+
+%macro ExceptTheFirstWord_SubListOf(List=);
+	%local L; %let L=%length(%TheFirstWordOf(List=&List));
+	%if &L<%length(&List) %then %left(%substr(&List,%eval(1+&L)));
+%mend;
+
+%macro ForEach(ItemRef,In=,Do=%nrstr(/* Nothing */));
+	%if %left(%trim(&In))^= %then %do;
+		%let &ItemRef=%TheFirstWordOf(List=&In);
+		%unquote(&Do);
+		%ForEach(&ItemRef,In=%ExceptTheFirstWord_SubListOf(List=&In),Do=&Do)
+	%end;
+%mend;
+
+%macro ComplementOfWord(w,In=);
+	%local _1stWord;
+	%if &In^= %then %do;
+		%let _1stWord=%TheFirstWordOf(List=&In);
+		%if &_1stWord=&w %then
+		%ComplementOfWord(&w,
+		In=%ExceptTheFirstWord_SubListOf(List=&In));
+		%else &_1stWord %ComplementOfWord(&w,
+		In=%ExceptTheFirstWord_SubListOf(List=&In));
+	%end;
+%mend;
+
+%macro PermutationOf(
+List,
+SelectedPath=,
+Execute=%nrstr(%put &SelectedPath;)
+);
+	%If &List= %Then
+	%unquote(&Execute) ;
+	%Else %do;
+		%ForEach(word, In=&List,
+		Do=%nrstr(
+		%PermutationOf(
+		%ComplementOfWord(&word,In=&List),
+		SelectedPath=&SelectedPath &word,
+		Execute=&Execute
+		)
+		)
+		)
+	%end;
+%mend;
+%PermutationOf(1 2 3 )
+
+
+
+%let c=0;
+%PermutationOf(1 2 3 4,Execute=%nrstr(%let c=%eval(&c+1);%put &c: &SelectedPath;))
+
+
+data Perm5;
+	%PermutationOf(1 2 3 ,Execute=%nrstr(
+	perm="&SelectedPath &word";output;))
+run;
diff --git a/get_label.sas b/get_label.sas
index 48db9a5..c9fcd21 100644
--- a/get_label.sas
+++ b/get_label.sas
@@ -1,4 +1,3 @@
-
 /*
 %put %get_label(sashelp.iris,SepalLength);
 */
@@ -6,11 +5,11 @@
 %macro get_label(data,variable);
 	%local label;  
    	%let dsid = %sysfunc(open(&data));
+	%let dnum=%sysfunc(varnum(&dsid,&variable));
+
   	%if &dsid %then %do;
-         %let label=%sysfunc(varlabel(&dsid,%sysfunc(varnum(&dsid,&variable))));
+         %let label=%sysfunc(varlabel(&dsid,&dnum));
          %let rc = %sysfunc(close(&dsid));		
    	%end;
     &label;
-%mend;  
-
-
+%mend;  
\ No newline at end of file
diff --git a/toDoc/isblank.sas b/toDoc/isblank.sas
new file mode 100644
index 0000000..2d0fc14
--- /dev/null
+++ b/toDoc/isblank.sas
@@ -0,0 +1,10 @@
+/*
+https://www.marc.info/?l=sas-l&m=142177161422037&w=2
+
+http://support.sas.com/resources/papers/proceedings09/022-2009.pdf
+by Chang Y. Chung, John King
+*/
+
+%macro isblank(param);
+ %sysevalf(%superq(param)=,boolean)
+%mend isblank; 
\ No newline at end of file