public PrgState Execute(PrgState state) { Stack <MyIDictionary <MyMap> > symTbl = state.GetSymTable(); IHeap <HMap> heap = state.GetHeap(); String v = this.var; int index = heap.GiveHeapLocation(); int val = exp.Eval(symTbl, heap); if (symTbl.ElementAt(0).IsDefined(v)) { symTbl.ElementAt(0).Update(v, index); } else { MyMap m = new MyMap(v, index); symTbl.ElementAt(0).Add(m); } heap.Add1(val); return(null); }