Writing the HTML renderer.

BBCodeNode.cs

@@ -47,7 +47,7 @@ public BBCodeNode(string TagName, string Attribute, bool IsSingular)
             if (TagName == "")
                 throw new ArgumentException("TagName cannot be empty");
 
-            this.TagName = TagName;
+            this.TagName = TagName.ToLower();
             this.Attribute = Attribute;
             this.Singular = IsSingular;
             children = new List<BBCodeNode>();
@@ -57,19 +57,7 @@ public BBCodeNode(string TagName, string Attribute, bool IsSingular)
         /// </summary>
         /// <param name="TagName">The node's tag name. Mandatory.</param>
         /// <param name="Attribute">The node's optional attribute. This may be an empty string or null.</param>
-        public BBCodeNode(string TagName, string Attribute)
-        {
-            if (TagName == null)
-                throw new ArgumentNullException("TagName cannot be null");
-
-            TagName = TagName.Trim();
-            if (TagName == "")
-                throw new ArgumentException("TagName cannot be empty");
-
-            this.TagName = TagName;
-            this.Attribute = Attribute;
-            children = new List<BBCodeNode>();
-        }
+        public BBCodeNode(string TagName, string Attribute) : this(TagName, Attribute, false) { }
         /// <summary>
         /// Creates a new BBCodeNode.
         /// </summary>

BBCodeTextNode.cs

@@ -13,6 +13,7 @@ class BBCodeTextNode : BBCodeNode
 
         public BBCodeTextNode(string InnerText)
         {
+            TagName = "span";
             Singular = true;
             text.Append(InnerText);
         }

Renderers/Html/HtmlRenderException.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace bbsharp.Renderers.Html
+{
+    class HtmlRenderException : Exception
+    {
+        public int Position { get; private set; }
+
+        public HtmlRenderException(string Message)
+            : base(Message)
+        { }
+    }
+}

Renderers/Html/Image.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Net;
+using System.Web;
+
+namespace bbsharp.Renderers.Html
+{
+    public static partial class HtmlRenderer
+    {
+        static string RenderImage(BBCodeNode Node, bool ThrowOnError)
+        {
+            if (Node.Children.Length != 1)
+                if (ThrowOnError)
+                    throw new HtmlRenderException("[img] tag does not to contain image URL");
+                else
+                    return "[img]" + Node.Children.ToHtml() + "[/img]";
+
+            if ((Node.Children[0] as BBCodeTextNode) == null)
+                if (ThrowOnError)
+                    throw new HtmlRenderException("[img] tag does not to contain image URL");
+                else
+                    return "[img]" + Node.Children.ToHtml() + "[/img]";
+
+            Uri src = null;
+            try
+            {
+                src = new Uri(Node.Children[0].ToString(), UriKind.Absolute);
+            }
+            catch (UriFormatException)
+            {
+                if (ThrowOnError)
+                    throw;
+                return "[img]" + Node.Children.ToHtml() + "[/img]";
+            }
+
+            if (!src.IsWellFormedOriginalString())
+                if (ThrowOnError)
+                    throw new HtmlRenderException("Image URL in [img] tag not well formed or relative");
+                else
+                    return "[img]" + Node.Children.ToHtml() + "[/img]";
+
+            if (!src.Scheme.Contains("http"))
+                if (ThrowOnError)
+                    throw new HtmlRenderException("Image URL scheme must be either HTTP or HTTPS");
+                else
+                    return "[img]" + Node.Children.ToHtml() + "[/img]";
+        }
+    }
+}

Renderers/Html/ToHtml.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Net;
+using System.Web;
+
+namespace bbsharp.Renderers.Html
+{
+    public static partial class HtmlRenderer
+    {
+        public static string ToHtml(this IEnumerable<BBCodeNode> Nodes)
+        {
+            return Nodes.ToHtml(false);
+        }
+        public static string ToHtml(this IEnumerable<BBCodeNode> Nodes, bool ThrowOnError)
+        {
+            StringBuilder html = new StringBuilder();
+
+            foreach (var node in Nodes)
+                html.Append(node.ToHtml(ThrowOnError));
+
+            return html.ToString();
+        }
+
+        static const string[] directBbToHtml = new string[] {
+            "b", "i", "u", "code", "del", "ins", "hr"
+        };
+
+        public static string ToHtml(this BBCodeNode Node)
+        {
+            return Node.ToHtml(false);
+        }
+        public static string ToHtml(this BBCodeNode Node, bool ThrowOnError)
+        {
+            if ((Node as BBCodeTextNode) != null)
+                return HttpUtility.HtmlEncode(Node.ToString());
+
+            if (directBbToHtml.Contains(Node.TagName))
+                if (Node.Singular)
+                    return "<" + Node.TagName + "/>";
+                else
+                    return "<" + Node.TagName + ">"
+                            + Node.ToHtml(ThrowOnError)
+                            + "</" + Node.TagName + ">";
+
+            switch (Node.TagName)
+            {
+                case "img":
+                    return RenderImage(Node, ThrowOnError);
+
+                default:
+                    if (Node.Singular)
+                        return "["
+                                + Node.TagName
+                                + Node.Attribute != null &&
+                                    Node.Attribute.Trim() != ""
+                                    ? "=" + HttpUtility.HtmlEncode(Node.Attribute)
+                                    : ""
+                                + "]";
+                    else
+                        return "["
+                                + Node.TagName
+                                + Node.Attribute != null &&
+                                    Node.Attribute.Trim() != ""
+                                    ? "=" + HttpUtility.HtmlEncode(Node.Attribute)
+                                    : "" 
+                                + "]"
+                                + Node.ToHtml(ThrowOnError)
+                                + "[/" + Node.TagName + "]";
+            }
+        }
+    }
+}

Renderers/Html/Unrecognised.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Net;
+using System.Web;
+
+namespace bbsharp.Renderers.Html
+{
+    public static partial class HtmlRenderer
+    {
+        //
+    }
+}

bbsharp.csproj

@@ -39,6 +39,10 @@
     <Reference Include="System.Data.Linq">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
+    <Reference Include="System.Web" />
+    <Reference Include="System.Web.Extensions">
+      <RequiredTargetFramework>3.5</RequiredTargetFramework>
+    </Reference>
     <Reference Include="System.XML" />
   </ItemGroup>
   <ItemGroup>
@@ -48,6 +52,10 @@
     <Compile Include="BBCodeParser.cs" />
     <Compile Include="BBCodeTextNode.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Renderers\Html\HtmlRenderException.cs" />
+    <Compile Include="Renderers\Html\Image.cs" />
+    <Compile Include="Renderers\Html\ToHtml.cs" />
+    <Compile Include="Renderers\Html\Unrecognised.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it.