Beispiel #1
0
 // TODO: The method apply() should be defined in class Node
 // to report an error.  It should be overridden only in classes
 // BuiltIn and Closure.
 //public /* override */ Node apply (Node args)
 //{
 //     return new StringLit("Error: BuiltIn.apply not yet implemented");
 //}
 public override Node apply(Node args)
 {
     int num = Util.expLength(args);
     bool flag = num > 2;
     if (flag)
     {
         Console.Error.WriteLine("Error: wrong number of arguments");
     }
     bool flag2 = num == 0; // length 0 arguments
     Node result;
     if (flag2)
     {
         result = this.apply0();
     }
     else //1 or 2 argument lengths
     {
         bool flag3 = num == 1; // length 1 arguments
         if (flag3)
         {
             result = this.apply1(args.getCar());
         }
         else
         {
             result = this.apply2(args.getCar(), args.getCdr().getCar());
         }
     }
     return result;
 }
Beispiel #2
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 public override Node eval(Node t, Environment env)
 {
     Node clauseList = t.getCdr();
     Node clause = clauseList.getCar();
     while(clause != Nil.getInstance())
     {
         Node predicate = clause.getCar().eval(env);
         if(predicate == BoolLit.getInstance(true) || predicate.getName() == "else")
         {
             Node expressionList = clause.getCdr();
             //evaluate all expressions and return the result of the last evaluation
             Node lastEval = expressionList.getCar().eval(env);
             //If there are more expressions to evaluate
             while(expressionList.getCdr() != Nil.getInstance())
             {
                 expressionList = expressionList.getCdr();
                 lastEval = expressionList.getCar().eval(env);
             }
             return lastEval;
         }
         clauseList = clauseList.getCdr();
         clause = clauseList.getCar();
     }
     //Does not yet handle else's
     return Nil.getInstance();
 }
        public override void print(Node t, int n, bool p)
        {
            for (int i = Console.CursorLeft; i < n; i++)
                Console.Write(" ");

            if (!p)
                Console.Write("(");
            //Print "lambda"
            t.getCar().print(n);
            Console.Write(" ");

            Node second = t.getCdr().getCar();
            if (second.isPair())
            {
                second.print(n, false);
            }
            Console.WriteLine();
            Node term = t.getCdr().getCdr();
            while(!term.isNull())
            {
                term.getCar().print(n + 4);
                term = term.getCdr();
                Console.WriteLine();
            }
            Nil.getNil().print(n,true);
        }
Beispiel #4
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        public override void print(Node t, int n, bool p)
        {
            if (!p)
            {
                var spaces = "";
                if (n >= 0) spaces = new string(' ', n);
                Console.Write(spaces + "(if ");
                if (t.getCdr().getCar().isPair())
                {
                    if((t.getCdr().getCar() as Cons).form is If ||
                        (t.getCdr().getCar() as Cons).form is Lambda ||
                        (t.getCdr().getCar() as Cons).form is Define)
                    t.getCdr().getCar().print(n+4, true);
                    else
                    {
                        t.getCdr().getCar().print(0, false);
                    }

                }
                else
                    t.getCdr().getCar().print(0, false);
                t = t.getCdr().getCdr();
                do
                {
                    Console.WriteLine("");
                    t.getCar().print(n + 4, false);
                    t = t.getCdr();
                } while (t.getCdr() != null);
                Console.WriteLine("");
                t.print(n, true);
            }
            else
            {
                var spaces = "";
                if (n >= 0) spaces = new string(' ', n);
                Console.Write("(if ");
                if (t.getCdr().getCar().isPair())
                {
                    if ((t.getCdr().getCar() as Cons).form is If ||
                        (t.getCdr().getCar() as Cons).form is Lambda ||
                        (t.getCdr().getCar() as Cons).form is Define)
                        t.getCdr().getCar().print(n+4, true);
                    else
                    {
                        t.getCdr().getCar().print(0, false);
                    }

                }
                t.getCdr().getCar().print(0, false);
                t = t.getCdr().getCdr();
                do
                {
                    Console.WriteLine("");
                    t.getCar().print(n + 4, false);
                    t = t.getCdr();
                } while (t.getCdr() != null);
                Console.WriteLine("");
                t.print(n, true);
            }
        }
 public override void print(Node t, int n, bool p)
 {
     for (int i = Console.CursorLeft; i < n; i++)
         Console.Write(" ");
     if (!p)
     {
         Console.Write("(");
     }
     //print "let"
     t.getCar().print(n);
     Console.WriteLine();
     Node rest = t.getCdr();
     if (rest.isPair())
     {
         rest.getCar().print(n + 4, false);
         Console.WriteLine();
         while ((rest = rest.getCdr()) != Nil.getNil())
         {
             rest.getCar().print(n + 4, false);
             Console.WriteLine();
         }
         Console.Write(")");
     }
     else t.getCdr().print(n, true);
 }
Beispiel #6
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        public Node evalLetBody(Node t, Environment env)
        {
            if(t == Nil.getInstance()) //This isn't correct. What do?
            {
                Node l = new Cons(new Nil(), new Nil()); //tree with pair of ()
                return l;
            }
            else
            {
                Node restBody = t.getCdr();
                Node variable = t.getCar().getCar();
                Node value = t.getCar().getCdr().getCar();

                if(variable.isSymbol()) //was value earlier, should be variable?
                {
                    env.define(variable,value.eval(env));
                    return evalLetBody(restBody, env);
                }
                else if(!variable.isPair()) //if it is a cons node. ???
                {
                    Console.Write("Error in Let->evalLetBody, variable is not valid");
                    return new Nil();

                }
                else if(variable.isNull())
                {
                    return new Nil();
                }
                else
                {
                    return variable.eval(env);
                }
            }
        }
Beispiel #7
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        public override void print(Node t, int n, bool p)
        {
            Console.Write("".PadLeft(n));
               if ( p != true)
               {
               Console.Write("(");
               }
               if(t.getCar().isPair())
               {
               t.getCar().print(0);
               }
               else
               {
               t.getCar().print(0, true);
               }
               Console.Write(" ");

            if(t.getCdr() is Nil)
            {
                Console.WriteLine(")");
            }
            else
            {
                t.getCdr().print(0, true);
            }
            //  Console.WriteLine();
        }
Beispiel #8
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        public override void print(Node t, int n, bool p)
        {
            // TODO: Implement this function.
            Console.Write("".PadLeft(n));
            Console.Write("(define ");

            Node name = t.getCdr().getCar();
            name.print(n);

            Console.Write(" ");

            Node definition = t.getCdr().getCdr().getCar();
            if (definition.isNull())
            {
                Console.Error.Write("Syntax error with DEFINE-definition");
            }
            else if (definition.isPair())
            {
                Console.WriteLine();
                //  Console.Write("".PadLeft(n+4));
                definition.print(n+4);
            }
            else
            {
                definition.print(n);
            }
            // made n to 0
            //  Console.WriteLine();
            Console.WriteLine("".PadLeft(n) + ")");
        }
Beispiel #9
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 // Key Deletion
 public bool Delete(double key)
 {
     bool value = KeyDeletion(null, root, key);
     if (root.key.Count == 0 && root.children[0] != null)
         root = root.children[0];
     return value;
 }
Beispiel #10
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        /* A O(n) iterative program for construction of BST from preorder traversal */
        public Node ConstuctTreeFromPreOrder(int[] preOrder)
        {
            Node root = new Node();
            root.data = preOrder[0];
            Stack<Node> _stack = new Stack<Node>();
            Node temp;
            for (int i = 1; i < preOrder.Length; i++)
            {
                temp = null;
                while (_stack.Count > 0 && preOrder[i] > _stack.Peek().data)
                {
                    temp = _stack.Pop();
                }

                if (temp != null)
                {
                    temp.right.data = preOrder[i];
                    _stack.Push(temp.right);
                }
                else
                {
                    temp.left.data = preOrder[i];
                    _stack.Push(temp.left);
                }
            }
            return root;
        }
        static Tree<int> ParseTree()
        {
            var nodes = new Dictionary<int, Node<int>>();
            Console.Write("Number of nodes:");
            int n = int.Parse(Console.ReadLine());
            Console.WriteLine("Start typing the node pairs separated by a single space");
            
            for (int i = 0; i < n-1; i++)
            {
                var pair = Console.ReadLine().Split();
                int first = int.Parse(pair[0]);
                int second = int.Parse(pair[1]);
                if (!nodes.ContainsKey(first))
                {
                    Node<int> parent = new Node<int>(first);
                    nodes.Add(first, parent);
                }

                if (!nodes.ContainsKey(second))
                {
                    Node<int> newNode = new Node<int>(second);
                    newNode.HasParent = true;
                    nodes.Add(second,newNode);
                    nodes[first].Children.Add(newNode);
                }

                nodes[first].Children.Add(nodes[second]);
                nodes[second].HasParent=true;

                
            }
            var root = nodes.First(x => x.Value.HasParent == false);
            var tree = new Tree<int>(root.Value);
            return tree;
        }
Beispiel #12
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 // TODO: The method apply() should be defined in class Node
 // to report an error.  It should be overridden only in classes
 // BuiltIn and Closure.
 public override Node apply (Node args)
 {
     Node param = fun.getCdr().getCar();
     int numArgs = Util.expLength(args);
     int numParam = Util.expLength(param);
     if (numArgs != numParam)
     {
         Console.Error.WriteLine("Error: wrong number of arguments");
     }
     Environment env1 = new Environment(env);
     while (param.isPair() && args.isPair())
     {
         Node id = param.getCar();
         Node val = args.getCar();
         env1.define(id, val);
         param = param.getCdr();
         args = args.getCdr();
     }
     while (param.isPair())
     {
         Node id = param.getCar();
         Node val = Nil.getInstance();
         env1.define(id, val);
         param = param.getCdr();
     }
     Node exp1 = fun.getCdr().getCdr();
     return Begin.evalBody(exp1, env1);
 }
Beispiel #13
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        public override void print(Node t, int n, bool p)
        {
            // TODO: Implement this function.
            //  Console.Write("".PadLeft(n));
            if (!p)
            {
                Console.Write("".PadLeft(n) + '(');
            }
            t.getCar().print(0, !p);
            //  if(!t.getCdr().isNull())
            //  {
            //      Console.Write(" ");
            //  }
            if(t.getCdr().isNull())
            {
                t.getCdr().print(0, true);
                //  Console.WriteLine();
            }
            else {
                Console.Write(" ");
                t.getCdr().print(n, true);
            }

            //  if(t.getCdr().isNull())
            //  {
            //      Console.WriteLine();
            //  }
        }
Beispiel #14
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 public override Node eval(Node t, Environment env)
 {
     if (t.getCdr() == Nil.getInstance())
     {
         Console.Error.WriteLine("Error: invalid argument");
         throw new InvalidOperationException();
     }
     if (t.getCdr().getCar().eval(env) != BoolLit.getInstance(false))
     {
         if (t.getCdr().getCdr() == Nil.getInstance())
         {
             Console.Error.WriteLine("Error: invalid argument");
             throw new InvalidOperationException();
         }
         return t.getCdr().getCdr().getCar().eval(env);
     }
     if (t.getCdr().getCdr() == Nil.getInstance())
     {
         Console.Error.WriteLine("Error: invalid argument");
         throw new InvalidOperationException();
     }
     if (t.getCdr().getCdr().getCdr() == Nil.getInstance())
     {
         return Nil.getInstance();
     }
     return t.getCdr().getCdr().getCdr().getCar().eval(env);
 }
Beispiel #15
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 public override Node eval(Node exp, Environment env)
 {
     int length = Util.expLength(exp);
     if (length < 3)
     {
         Console.Error.WriteLine("Error: invalid expression");
         return Nil.getInstance();
     }
     Node second = exp.getCdr().getCar();
     while (second.isPair())
     {
         if (Util.expLength(second.getCar()) != 2)
         {
             Console.Error.WriteLine("Error: invalid expression");
             return Nil.getInstance();
         }
         second = second.getCdr();
     }
     second = exp.getCdr().getCar();
     Environment env1 = new Environment(env);
     while (second.isPair())
     {
         Node id = second.getCar().getCar();
         Node val = second.getCar().getCdr().getCar();
         env1.define(id, val);
         second = second.getCdr();
     }
     Node exp1 = exp.getCdr().getCdr();
     return Begin.evalBody(exp1, env1);
 }
Beispiel #16
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 public override Node eval(Node t, Environment e)
 {
     if(t.getCdr() is Closure)
         return e.lookup(t.getCar()).apply(t.getCdr());
     else
     {
         Node args = t.getCdr();
         Node param;
         if (args.getCar().isSymbol())
             param = new Cons(e.lookup((Node)args.GetCar()), Nil.getInstance());
         else
             param = new Cons((Node)args.GetCar(), Nil.getInstance());
         Node currentNode = param;
         args = args.getCdr();
         while (args != Nil.getInstance())
         {
             if (args.getCar().isSymbol())
                 currentNode.setCdr(new Cons(e.lookup(args.getCar()), Nil.getInstance()));
             else
                 currentNode.setCdr(new Cons(args.getCar(), Nil.getInstance()));
             currentNode = currentNode.getCdr();
             args = args.getCdr();
         }
         return e.lookup(t.getCar()).apply(param);
     }
 }
Beispiel #17
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 public override void print(Node t, int n, bool p)
 {
     // print leading spaces and '
     if (n < 0)
     {
         n = -(n + 1);
     }
     Console.Write(new string(' ', n) + "'");
     // if quote a list
     if (t.getCdr().getCar().isPair())
     {
         // this while is to print following quote as ' to get the sample output
         while (t.getCdr().getCar().getCar().isSymbol() 
             && ((Ident) t.getCdr().getCar().getCar()).getName().Equals("quote"))
         {
             Console.Write("'");
             t = t.getCdr().getCar();
         }
         // using the Regular form to print quoted list
         Special v = new Regular();
         v.print(t.getCdr().getCar(), 0, false);
         // if the caller asks for change line
         if (n > 0)
         {
             Console.WriteLine();
         }
     }
     // if quote a single element
     else
     {
         t.getCdr().getCar().print(0);
     }
 }
Beispiel #18
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 //Function for pairing up arguments with corresponding symbols
 private static void pairup(Node parms, Node args, Environment env)
 {
     //if null return nothing
     if (parms.isNull() && args.isNull())
     {
         return;
     }
     //check the symbol type
     if (parms.isSymbol())
     {
         env.define(parms, args);
     }
     //depending on the parameter, check the # of required valid arguments
     else if (parms.isNull() || args.isNull())
     {
         Console.get_Error().WriteLine("Error: wrong number of arguments");
     }
     //look for values in different env w/ closure pointer? idk how to explain this
     else if (parms.isPair() && args.isPair())
     {
         env.define(parms.getCar(), args.getCar());
         Closure.pairup(parms.getCdr(), args.getCdr(), env);
     }
     else
     {
         Console.get_Error().WriteLine("Error: invalid expression");
     }
 }
Beispiel #19
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        public override Node eval(Node exp, Environment env)
        {
            int length = Util.expLength(exp);
            if (length < 3)
            {
                Console.Error.WriteLine("Error: invalid expression");
                return Nil.getInstance();
            }
            Node second = exp.getCdr().getCar();
            Node name, value;
            if (length == 3 && second.isSymbol())
            {
                name = second;
                value = exp.getCdr().getCdr().getCar().eval(env);
                env.define(name, value);
                return null;
            }
            if (!second.isPair())
            {
                Console.Error.WriteLine("Error: invalid expression");
                return Nil.getInstance();
            }
            name = second.getCar();
            Node lambda = exp.getCdr();
            lambda.setCar(second.getCdr());
            lambda = new Cons(new Ident("lambda"), lambda);
            value = lambda.eval(env);
            env.define(name, value);

            return null;
        }
Beispiel #20
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        public override void print(Node t, int n, bool p)
        {
            // TODO: Implement this function.
            Console.Write("".PadLeft(n));
            Console.WriteLine("(let");
            Node bindings = t.getCdr().getCar();

            if (bindings.isPair())
            {
                bindings.print(0,false);
            }
            else
            {
                Console.Error.WriteLine("Syntax error for LET-BINDINGS");
            }

            Console.Write("".PadLeft(n));
            Node body = t.getCdr().getCdr();

            if (body.isPair())
            {
                body.print(n+4, true);
            }
            else
            {
                Console.Error.WriteLine("Syntax error for LET-BODY");
            }
            Console.Write("".PadLeft(n)+ ")");
        }
Beispiel #21
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 public override Node eval(Node t, Environment e)
 {
     while (t.getCdr() != Nil.getInstance())
     {
         t = t.getCdr();
         if (t.getCar().GetType() != typeof(Cons))
         {
             Console.Error.WriteLine("Error: invalid argument");
             throw new InvalidOperationException();
         }
         if (t.getCar().getCar().eval(e) == BoolLit.getInstance(true))
         {
             t = t.getCar();
             while(t.getCdr() != Nil.getInstance())
             {
                 t = t.getCdr();
                 if (t.getCdr() == Nil.getInstance()) break;
                 t.getCar().eval(e);
             }
             return (Node)t.getCar().eval(e);
         }
         else if (t.getCar().getCar().eval(e) != BoolLit.getInstance(false))
         {
             Console.Error.WriteLine("Error: invalid argument");
             throw new InvalidOperationException();
         }
     }
     return Nil.getInstance();
 }
Beispiel #22
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 public void assign(Node id, Node val)
 {
     // TODO: implement this function
        // create name
       //  if (search for name in either frame or environment)
        //     name = newvalue
 }
Beispiel #23
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 // REMEMBER: If not explictly false, then true.
 public Node eval(Node t, Environment e)
 {
     Node cond = t.getCdr().getCar(); // condition -> cadr(exp)
     if (cond == null)
     {
         Console.Error.WriteLine("Error: Null in Condition");
     }
     Node ifTrue = t.getCdr().getCdr().getCar(); // true -> caddr(exp)
     if (ifTrue == null)
     {
         Console.Error.WriteLine("Error: Null in True/If");
     }
     Node ifFalse = t.getCdr().getCdr().getCdr().getCar(); // false -> cadddr(exp)
     if (ifFalse == null)
     {
         Console.Error.WriteLine("Error: Null in False/Else");
     }
     bool checkTrueResult = checkTrue(t, e);
     if (checkTrueResult == true)
     {
         return ifTrue.eval(ifTrue, e);
     }
     else
     {
         return ifFalse.eval(ifFalse, e);
     }
 }
Beispiel #24
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        public override void print(Node t, int n, bool p)
        {
            Console.Write("".PadLeft(n));
               Console.Write("(lambda");

               Node Num2Node = t.getCdr().getCar();
               if (Num2Node.isPair())
               {
             Num2Node.print(0,false);
               }
               else
               {
              Console.Error.Write("Syntax Error with Lambda (Num2Node)");
               }

               Console.Write("".PadLeft(n));

               Node Num3Node = t.getCdr().getCdr().getCar();

               if( Num3Node.isPair())
               {
               Num3Node.print(n+4, false);
               }
               else
               {
               Console.Error.Write("Syntax Error with Lambda (Num3Node)");
               }
               Console.Write("".PadLeft(n));
        }
 private bool CompareTrees(Node Root1, Node Root2)
 {
     if (Root1 == null || Root2 == null)
         return true;
     if (Root1.Data != Root2.Data)
         return false;
     return CompareTrees(Root1.Left, Root2.Left) || CompareTrees(Root1.Right, Root2.Right);
 }
Beispiel #26
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 public void TestSerialize()
 {
     var node = new Node();
     node.Key = "test";
     var payload = this.serializer.Marshal(node);
     var result = this.serializer.Unmarshal(payload);
     Assert.AreEqual(node, result);
 }
Beispiel #27
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 public override Node eval(Node t, Environment env)
 {
     //arg1: set!
     //arg2: variable
     //arg3: value
     env.assign(t.getCdr().getCar(), t.getCdr().getCdr().getCar().eval(env));
     return new StringLit("set done");
 }
Beispiel #28
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 private static void GetDepthRecurively(Node node, ref int depth)
 {
     if (node.Children.Count > 0)
     {
         depth += 1;
         GetDepthRecurively(node.Children.FirstOrDefault(), ref depth);
     }
 }
Beispiel #29
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 // TODO: The method apply() should be defined in class Node
 // to report an error.  It should be overridden only in classes
 // BuiltIn and Closure.
 public override Node apply(Node args)
 {
     Node car = this.fun.getCdr().getCar();
     Node cdr = this.fun.getCdr().getCdr();
     Environment environment = new Environment(this.env);
     Closure.pairup(car, args, environment);
     return Util.begin(cdr, environment);
 }
Beispiel #30
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 public override Node eval(Node t, Environment env)
 {
     Node bodystart = t.getCdr().getCar();
     Node expression = t.getCdr().getCdr().getCar();
     Environment e = new Environment(env);
     bodystart = evalLetBody(bodystart, e); //Should we be returning bodystart?
     return expression.eval(e); //Why return e?
 }
 public Node(int key)
 {
     this.leftNode = null;
     this.rightNode = null;
     this.key = key;
 }
Beispiel #32
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 public override void print(Node t, int n, bool p)
 {
     Printer.printRegular(t, n, p);
 }
Beispiel #33
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 public BuiltIn(Node s)
 {
     symbol = s;
 }
Beispiel #34
0
 public Node eval(Node t, Environment env)
 {
     Console.Error.WriteLine("Error in eval BuiltIN");
     return(Nil.getInstance());
 }
Beispiel #35
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        public override Node apply(Node args)
        {
            if (args == null)
            {
                return(null);
            }

            String symbolType = symbol.getName();
            Node   arg1       = args.getCar();
            Node   arg2       = args.getCdr();

            if (arg1.isNull())
            {
                arg1 = Nil.getInstance();
            }
            if (arg2.isNull())
            {
                arg2 = Nil.getInstance();
            }
            else
            {
                arg2 = args.getCdr().getCar();
            }

            if (symbolType.Equals("b+"))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new IntLit(arg1.getValue() + arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b+"));
                }
            }
            if (symbolType.Equals("b-"))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new IntLit(arg1.getValue() - arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b-"));
                }
            }
            if (symbolType.Equals("b*"))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new IntLit(arg1.getValue() * arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b*"));
                }
            }
            if (symbolType.Equals("b/"))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new IntLit(arg1.getValue() / arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b/"));
                }
            }
            if (symbolType.Equals("b="))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new BoolLit(arg1.getValue() == arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b="));
                }
            }
            if (symbolType.Equals("b<"))
            {
                if (arg1.isNumber() & arg2.isNumber())
                {
                    return(new BoolLit(arg1.getValue() < arg2.getValue()));
                }
                else
                {
                    return(new StringLit("Error: Both arguments must be numbers for b<"));
                }
            }

            if (symbolType.Equals("null?"))
            {
                return(new BoolLit(arg1.isNull()));
            }
            if (symbolType.Equals("number?"))
            {
                return(new BoolLit(arg1.isNumber()));
            }
            if (symbolType.Equals("pair?"))
            {
                return(new BoolLit(arg1.isPair()));
            }
            if (symbolType.Equals("symbol?"))
            {
                return(new BoolLit(arg1.isSymbol()));
            }
            if (symbolType.Equals("procedure?"))
            {
                return(new BoolLit(arg1.isProcedure()));
            }

            if (symbolType.Equals("car"))
            {
                if (arg1.isNull())
                {
                    return(arg1);
                }
                return(arg1.getCar());
            }
            if (symbolType.Equals("cdr"))
            {
                if (arg1.isNull())
                {
                    return(arg1);
                }
                return(arg1.getCdr());
            }
            if (symbolType.Equals("set-car!"))
            {
                arg1.setCar(arg2);
                return(arg1);
            }
            if (symbolType.Equals("set-cdr!"))
            {
                arg1.setCdr(arg2);
                return(arg1);
            }

            if (symbolType.Equals("cons"))
            {
                return(new Cons(arg1, arg2));
            }

            if (symbolType.Equals("eq?"))
            {
                return(new BoolLit(arg1 == arg2));
            }

            if (symbolType.Equals("display"))
            {
                return(arg1);
            }

            if (symbolType.Equals("write"))
            {
                //write calls your pretting printer
                arg1.print(0);
                return(new StringLit(""));
            }

            if (symbolType.Equals("eval"))
            {
                //eval calls your C# eval() function
                return(eval(arg1, env));
            }

            if (symbolType.Equals("apply"))
            {
                //apply calls your C# apply function
                return(arg1.apply(arg2));
            }

            if (symbolType.Equals("newline"))
            {
                return(new StringLit(""));
            }

            if (symbolType.Equals("read"))
            {
                Scanner     io      = new Scanner(Console.In);
                TreeBuilder tree    = new TreeBuilder();
                Parser      parse   = new Parser(io, tree);
                Node        theNode = (Node)parse.parseExp();
                return(theNode);
            }

            if (symbolType.Equals("interaction-environment"))
            {
                env.print(0);
            }
            else
            {
                arg1.print(0);
                return(Nil.getInstance());
            }

            return(Nil.getInstance());
        }
Beispiel #36
0
 public override Node eval(Environment env, Node args = null)
 {
     return(new StringLit(stringVal));
 }