Swap the values of two similarly-defined variables without a temporary holding variable

THIS CAN BE ACHIEVED BY USING %BITXOR BIF

This code fragment illustrates that technique.
D Var1 s 8a
D Var2 s 8a

/free
Var1 = 'MITH ARG';
Var2 = 'ARG MITH';

Var1 = %bitxor(Var1: Var2);
Var2 = %bitxor(Var1: Var2);
Var1 = %bitxor(Var1: Var2);
after this code runs, Var1 has the value "ARG MITH" and Var2 has the value "MITH ARG"