1proc(x,y) [x|-> ] {
2  x->tl = y;
3} [x|-> tl:y]
4
5main(x,z;)[emp] { 
6  x = new(); z= new(); x->tl=3; z->tl=3;
7  proc(x,4) || proc(z,5);
8} [x|->tl:4 * z|-> tl:5]