Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Sprache;
using System.IO;

namespace XmlExample
{
    public class Document
    {
        public Node Root;

        public override string ToString()
        {
            return Root.ToString();
        }
    }

    public class Item { }

    public class Content : Item
    {
        public string Text;

        public override string ToString()
        {
            return Text;
        }
    }

    public class Node : Item
    {
        public string Name;
        public IEnumerable<Item> Children;

        public override string ToString()
        {
            if (Children != null)
                return string.Format("<{0}>", Name) +
                    Children.Aggregate("", (s, c) => s + c) +
                    string.Format("</{0}>", Name);
            return string.Format("<{0}/>", Name);
        }
    }

    public static class XmlParser
    {
        static CommentParser Comment = new CommentParser("<!--", "-->", "\r\n");

        static readonly Parser<string> Identifier =
            from first in Parse.Letter.Once()
            from rest in Parse.LetterOrDigit.XOr(Parse.Char('-')).XOr(Parse.Char('_')).Many()
            select new string(first.Concat(rest).ToArray());

        static Parser<T> Tag<T>(Parser<T> content)
        {
            return from lt in Parse.Char('<')
                   from t in content
                   from gt in Parse.Char('>').Token()
                   select t;
        }

        static readonly Parser<string> BeginTag = Tag(Identifier);

        static Parser<string> EndTag(string name)
        {
            return Tag(from slash in Parse.Char('/')
                       from id in Identifier
                       where id == name
                       select id).Named("closing tag for " + name);
        }

        static readonly Parser<Content> Content =
            from chars in Parse.CharExcept('<').Many()
            select new Content { Text = new string(chars.ToArray()) };

        static readonly Parser<Node> FullNode =
            from tag in BeginTag
            from nodes in Parse.Ref(() => Item).Many()
            from end in EndTag(tag)
            select new Node { Name = tag, Children = nodes };

        static readonly Parser<Node> ShortNode = Tag(from id in Identifier
                                                     from slash in Parse.Char('/')
                                                     select new Node { Name = id });

        static readonly Parser<Node> Node = ShortNode.Or(FullNode);

        static readonly Parser<Item> Item =
            from leading in Comment.MultiLineComment.Many()
            from item in Node.Select(n => (Item)n).XOr(Content)
            from trailing in Comment.MultiLineComment.Many()
            select item;

        public static readonly Parser<Document> Document =
            from leading in Parse.WhiteSpace.Many()
            from doc in Node.Select(n => new Document { Root = n }).End()
            select doc;
    }

    class Program
    {
        static void Main()
        {
            string input = File.ReadAllText("TestFile.xml", Encoding.UTF8);
            var parsed = XmlParser.Document.Parse(input);
            Console.WriteLine(parsed);
            Console.ReadKey(true);
        }
    }
}