//Regla 43 y 52
        public Expresion(ref Stack <StackElement> pila) : base(45)
        {
            expr = null;
            ter  = null;
            pila.Pop();
            StackElement elem = pila.Pop(); //quita termino o )

            if (elem is Termino)
            {
                ter = elem as Termino;
            }
            else if (elem is Terminal)
            {
                pila.Pop();
                expr = pila.Pop() as Expresion;
                pila.Pop();
                pila.Pop(); //quita (
            }
        }
 public Expresion() : base(45)
 {
     expr = null; ter = null; containsChildren = false;
 }
        public string Analiza(string text)
        {
            l = new Lexical(text);

            stack            = new StringBuilder();
            SyntacticalStack = new Stack <StackElement>();
            int x = 0;  //Fila
            int y = 0;  //Columna
            int r = 0;  //Resultado (regla, desplazamiento o aceptacion)

            //int pops = 0;   //Cantidad de elementos que produce la regla
            bool error     = false; //Bandera que detiene el ciclo
            bool newSymbol = true;  //Decide si se necesita un nuevo simbolo del Lexico o no

            SyntacticalStack.Push(new State(0));
            //StackElement Root = new StackElement()

            Symbol currentSymbol = new Symbol();

            while (!error)
            {
                if (newSymbol)
                {
                    currentSymbol = l.NextSymbol();
                    DataGridViewRow row = new DataGridViewRow();

                    row.CreateCells(SymbolsTable);
                    row.Cells[0].Value = currentSymbol.value;
                    row.Cells[1].Value = currentSymbol.name;
                    row.Cells[2].Value = ((int)currentSymbol.type).ToString();
                    if (((int)currentSymbol.type) == -1)
                    {
                        foreach (DataGridViewCell cell in row.Cells)
                        {
                            cell.Style.BackColor = System.Drawing.Color.Red;
                            cell.Style.ForeColor = System.Drawing.Color.White;
                        }
                        error = true;
                    }
                    SymbolsTable.Rows.Add(row);
                }
                y = ((State)SyntacticalStack.Peek()).transicion;
                x = (int)currentSymbol.type;

                r = LRTable[y][x];

                if (r > 0)
                {
                    //Desplazamiento
                    SyntacticalStack.Push(new Terminal(currentSymbol));
                    SyntacticalStack.Push(new State(r));
                    newSymbol = true;
                    GeneratePrintedStack();
                }
                else if (r < 0) //Reglas
                {
                    r = Math.Abs(r) - 1;
                    if (r == 0)
                    {
                        //Cadena Aceptada
                        break;
                    }
                    NonTerminal element = null;
                    switch (r)
                    {
                    case 1:     //<programa> ::= <Definiciones>
                        element = new Programa(ref SyntacticalStack);
                        break;

                    case 2:     //<Definiciones> ::= \e
                        element = new Definiciones();
                        break;

                    case 3:     //<Definiciones> ::= <Definicion> <Definiciones>
                        element = new Definiciones(ref SyntacticalStack);
                        break;

                    case 4:     //<Definicion> ::= <DefVar>
                    case 5:     //<Definicion> ::= <DefFunc>
                        element = new Definicion(ref SyntacticalStack);
                        break;

                    case 6:     //<DefVar> ::= tipo identificador <ListaVar> ;
                        element = new DefVar(ref SyntacticalStack);
                        break;

                    case 7:     //<ListaVar> ::= \e
                        element = new ListaVar();
                        break;

                    case 8:      //<ListaVar> ::= , id <ListaVar>
                        element = new ListaVar(ref SyntacticalStack);
                        break;

                    case 9:     //<DefFunc> ::= tipo id ( <Parametros> ) <BloqFunc>
                        element = new DefFunc(ref SyntacticalStack);
                        break;

                    case 10:     //<Parametros> ::= \e
                        element = new Parametros();
                        break;

                    case 11:     //<Parametros> ::= tipo id <ListaParam>
                        element = new Parametros(ref SyntacticalStack);
                        break;

                    case 12:     //R12 <ListaParam> ::= \e
                        element = new ListaParam();
                        break;

                    case 13:     //<ListaParam> ::= , tipo id <ListaParam>
                        element = new ListaParam(ref SyntacticalStack);
                        break;

                    case 14:     //<BloqFunc> ::= { <DefLocales> }
                        element = new BloqFunc(ref SyntacticalStack);
                        break;

                    case 15:     //<DefLocales> ::= \e
                        element = new DefLocales();
                        break;

                    case 16:     //<DefLocales> ::= <DefLocal> <DefLocales>
                        element = new DefLocales(ref SyntacticalStack);
                        break;

                    case 17:     //<DefLocal> ::= <DefVar>
                        element = new DefLocal(ref SyntacticalStack);
                        break;

                    case 18:     //<DefLocal> ::= <Sentencia>
                        element = new DefLocal(ref SyntacticalStack);
                        break;

                    case 19:     //<Sentencias> ::= \e
                        element = new Sentencias();
                        break;

                    case 20:     //<Sentencias> ::= <Sentencia> <Sentencias>
                        element = new Sentencias(ref SyntacticalStack);
                        break;

                    case 21:     //<Sentencia> ::= identificador = <Expresion> ;
                        element = new Asignacion(ref SyntacticalStack);
                        break;

                    case 22:     //<Sentencia> ::= if ( <Expresion> ) <SentenciaBloque> <Otro>
                        element = new If(ref SyntacticalStack);
                        break;

                    case 23:     //<Sentencia> ::= while ( <Expresion> ) <Bloque>
                        element = new While(ref SyntacticalStack);
                        break;

                    case 24:     //<Sentencia> ::= return <ValorRegresa> ;
                        element = new Return(ref SyntacticalStack);
                        break;

                    case 25:     //<Sentencia> ::= <LlamadaFunc> ;
                        element = new SentenciaLLama(ref SyntacticalStack);
                        break;

                    case 26:     //<Otro> ::= \e
                        element = new Otro();
                        break;

                    case 27:     //<Otro> ::= else <SentenciaBloque>
                        element = new Otro(ref SyntacticalStack);
                        break;

                    case 28:     //<Bloque> ::= { <Sentencias> }
                        element = new Bloque(ref SyntacticalStack);
                        break;

                    case 29:     //<ValorRegresa> ::= \e
                        element = new ValorRegresa();
                        break;

                    case 30:     //<ValorRegresa> ::= <Expresion>
                        element = new ValorRegresa(ref SyntacticalStack);
                        break;

                    case 31:     //<Argumentos> ::= \e
                        element = new Argumentos();
                        break;

                    case 32:     //<Argumentos> ::= <Expresion> <ListaArgumentos>
                        element = new Argumentos(ref SyntacticalStack);
                        break;

                    case 33:     //<ListaArgumentos> ::= \e
                        element = new ListaArgumentos();
                        break;

                    case 34:     //<ListaArgumentos> ::= , <Expresion> <ListaArgumentos>
                        element = new ListaArgumentos(ref SyntacticalStack);
                        break;

                    case 35:     //<Termino> ::= <LlamadaFunc>
                    case 36:     //<Termino> ::= identificador
                    case 37:     //<Termino> ::= entero
                    case 38:     //<Termino> ::= real
                    case 39:     //<Termino> ::= cadena
                        element = new Termino(ref SyntacticalStack);
                        break;

                    case 40:     //<LlamadaFunc> ::= identificador ( <Argumentos> )
                        element = new LlamadaFunc(ref SyntacticalStack);
                        break;

                    case 41:     //<SentenciaBloque> ::= <Sentencia>
                    case 42:     //<SentenciaBloque> ::= <Bloque>
                        element = new SentenciaBloque(ref SyntacticalStack);
                        break;

                    case 43:     //<Expresion> ::= ( <Expresion> )
                        element = new Expresion(ref SyntacticalStack);
                        break;

                    case 44:     //<Expresion> ::= opSuma <Expresion>
                    case 45:     //<Expresion> ::= opNot <Expresion>
                        element = new Operacion1(ref SyntacticalStack);
                        break;

                    case 46:     //<Expresion> ::= <Expresion> opMul <Expresion>
                    case 47:     //<Expresion> ::= <Expresion> opSuma <Expresion>
                    case 48:     //<Expresion> ::= <Expresion> opRelac <Expresion>
                    case 49:     //<Expresion> ::= <Expresion> opIgualdad <Expresion>
                    case 50:     //<Expresion> ::= <Expresion> opAnd <Expresion>
                    case 51:     //<Expresion> ::= <Expresion> opOr <Expresion>
                        element = new Operacion2(ref SyntacticalStack);
                        break;

                    case 52:     //<Expresion> ::= <Termino>
                        element = new Expresion(ref SyntacticalStack);
                        break;

                    default:
                        //pops = Rules.ElementAt(r - 1).TotalProductions;

                        //if (pops > 0)
                        //{
                        //    while (pops > 0)
                        //    {
                        //        SyntacticalStack.Pop();
                        //        SyntacticalStack.Pop();
                        //        pops--;
                        //    }
                        //}

                        break;
                    }
                    y = ((State)SyntacticalStack.Peek()).transicion;

                    x = element.columna;
                    SyntacticalStack.Push(element);

                    r = LRTable[y][x];
                    SyntacticalStack.Push(new State(r));
                    newSymbol = false;
                    GeneratePrintedStack();
                    Root = element;
                }
                else
                {
                    error = true;
                }
            }

            StringBuilder result = new StringBuilder();

            if (error)
            {
                result.Append("Error en símbolo: " + currentSymbol.value + "\tLinea: " + currentSymbol.linea + "\r\n");
            }
            return(result.ToString());
        }