IronPyton分析表达式

全部代码如下：

using System;
using System.Collections.Generic;
using System.Text;
using IronPython.Runtime;
using IronPython.Compiler;
using IronPython.Compiler.Ast;

namespace ConsoleApplication1 {
    class Program {
        static void Main(string[] args) {
            //string expression = "Sum(ActiveObject.Parent.Discount*ActiveObject.PrimePrice*Amount)";
            string expression = "Sum(ActiveObject.Parent.Details,\"Money\")*ActiveObject.ExchangeRate";
            SystemState state = new SystemState();
            CompilerContext context = new CompilerContext();
            Parser p = Parser.FromString(state, context, expression);
            IronPython.Compiler.Ast.Expression ex = p.ParseTestListAsExpression();
            MyWalker w = new MyWalker();
            ex.Walk(w);
            foreach (string item in w._expressions) {
                Console.WriteLine(item);                
            }
            Console.ReadLine();

        }
        class MyWalker : AstWalker {
            private Stack<string> _stack;
            public List<string> _expressions;
            public MyWalker() {
                _stack = new Stack<string>();
                _expressions = new List<string>();
            }
            public override bool Walk(FieldExpression node) {
                //        node.Target.ToString()    "IronPython.Compiler.Ast.FieldExpression:Parent"    string
                //        node.Name.ToString()    "Discount"    string
                string name = node.Name.ToString();
                if (_stack.Count > 0) {
                    if (_stack.Peek() != name) {
                        _stack.Push(name);
                    }
                }
                else {
                    _stack.Push(name);
                }
                string[] temps = node.Target.ToString().Split(':');
                string target = temps[1];
                _stack.Push(target);
                if (target == "ActiveObject") {
                    //弹出
                    StringBuilder expressionBuilder = new StringBuilder();
                    while (_stack.Count > 1) {
                        expressionBuilder.Append(_stack.Pop())
                       .Append(".");
                    }
                    expressionBuilder.Append(_stack.Pop());
                    _expressions.Add(expressionBuilder.ToString());
                }
                
                //Console.WriteLine("NodeName = "+node.Name + ",      NodeTrage = " + node.Target);
                
                

                return base.Walk(node);
            }

            public override bool Walk(ConstantExpression node) {
                int lastIndex = this._expressions.Count - 1;
                if (lastIndex > -1) {
                    this._expressions[lastIndex] = this._expressions[lastIndex] + "." + node.Value.ToString();
                }
                return base.Walk(node);
            }

        }
    }
}