/** Affectation, ExpVar = Exp. */
public class ExpAff extends Exp {
  public ExpVar v;
  public Exp e;
  public ExpAff(ExpVar v, Exp e) { super(v, e); this.v = v; this.e = e; }
  public Integer eval(){
    Integer res = e.eval();
    parser.symTab.put(v.name,res);
    return res;
  }
}