lag addition

[PBsas]

Can you please help with following?

data a;
input var1 $;
datalines;
a
b
c
d
e
;
run;

what I need is:

var1	var2
a	a
b	a-b
c	a-b-c
d	a-b-c-d
e	a-b-c-d-e

[Reeza]

RETAIN + CATX. 

[PBsas]

data b ;
    length cat $200 ;
set a ;
retain cat;
cat = catx('-',lag(var1),var1) ;
run ;

This is what I have but not getting results i want.

[Reeza · Accepted solution]

cat = catx('-',lag(var1),var1) ;

That doesn't make sense, you want to add the new variable, not the previous variable1 and current variable.

cat = catx('-',cat,var1) ;

[PBsas]

Thank you @Reeza