TinyLisp: A Language and Parser to See LINQ Expressions in Action

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows;
using System.Windows.Documents;
using le = System.Linq.Expressions;

namespace TinyLisp {
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e) {

            string sExpression = Input.Text;
            try {
                CharStream s = new CharStream(sExpression);
                CodeNode nExpression = new ExpressionNode(s);

                // Show in tree
                List<CodeNode> ln = new List<CodeNode>() { nExpression };
                tvAst.ItemsSource = ln;

                // convert to Linq.Expression
                le.Expression eExpression = nExpression.ToExpression();
                
                // put it into a Lambda
                le.Expression<Func<int>> lExpression = le.Expression.Lambda<Func<int>>(eExpression);
                
                // Compile the lambda
                Func<int> fExpression = lExpression.Compile();             
           
                
                // display the Linq Expression
                // wrap expression in ExpressionAdapter and then List<ExpressionAdapter> (because a Treeview.ItemSource expects an IEnumerable) and bind TreeView to it
                List<ExpressionAdapter> l = new List<ExpressionAdapter>() { new ExpressionAdapter(lExpression, "Expression") };
                tvExpr.ItemsSource = l;

                // and execute the compiled lambda to see the result
                MessageBox.Show("the answer is " + fExpression(), "That's easy!");

            } catch (Exception ex) { MessageBox.Show(ex.Message, "Hmmm, you might want to check that again"); }
        }

        

       
    }   
}