Begin implementation of context scopes.

Instead of context data being a single object, it now supports the same
scoping rules as keys.
Now the #index tag is always available.

mustache-sharp.test/FormatCompilerTester.cs

@@ -1093,7 +1093,7 @@ Item Number: foo<br />
                 return new TagParameter[] { new TagParameter("param") { IsRequired = false, DefaultValue = 123 } };
             }
 
-            public override void GetText(TextWriter writer, Dictionary<string, object> arguments, object contextData)
+            public override void GetText(TextWriter writer, Dictionary<string, object> arguments, Scope contextScope)
             {
                 writer.Write(arguments["param"]);
             }
@@ -1168,5 +1168,23 @@ Your order total was: $7.50";
         }
 
         #endregion
+
+        #region Context Variables
+
+        /// <summary>
+        /// We will use the index variable to determine whether or not to print out a line.
+        /// </summary>
+        [TestMethod]
+        public void TestCompile_CanUseContextVariablesToMakeDecisions()
+        {
+            FormatCompiler compiler = new FormatCompiler();
+            const string format = @"{{#each this}}{{#if @index}}{{#index}}{{/if}}{{/each}}";
+            Generator generator = compiler.Compile(format);
+            string actual = generator.Render(new int[] { 1, 1, 1, 1, });
+            string expected = "123";
+            Assert.AreEqual(expected, actual, "The numbers were not valid.");
+        }
+
+        #endregion
     }
 }

mustache-sharp/ArgumentCollection.cs

@@ -50,9 +50,10 @@ namespace Mustache
         /// <summary>
         /// Substitutes the key placeholders with their respective values.
         /// </summary>
-        /// <param name="scope">The current lexical scope.</param>
+        /// <param name="keyScope">The key/value pairs in the current lexical scope.</param>
+        /// <param name="contextScope">The key/value pairs in current context.</param>
         /// <returns>A dictionary associating the parameter name to the associated value.</returns>
-        public Dictionary<string, object> GetArguments(KeyScope scope)
+        public Dictionary<string, object> GetArguments(Scope keyScope, Scope contextScope)
         {
             Dictionary<string, object> arguments = new Dictionary<string,object>();
             foreach (KeyValuePair<TagParameter, string> pair in _argumentLookup)
@@ -62,13 +63,27 @@ namespace Mustache
                 {
                     value = pair.Key.DefaultValue;
                 }
+                else if (pair.Value.StartsWith("@"))
+                {
+                    value = contextScope.Find(pair.Value.Substring(1));
+                }
                 else
                 {
-                    value = scope.Find(pair.Value);
+                    value = keyScope.Find(pair.Value);
                 }
                 arguments.Add(pair.Key.Name, value);
             }
             return arguments;
         }
+
+        public Dictionary<string, object> GetArguments()
+        {
+            Dictionary<string, object> arguments = new Dictionary<string, object>();
+            foreach (KeyValuePair<TagParameter, string> pair in _argumentLookup)
+            {
+                arguments.Add(pair.Key.Name, pair.Value);
+            }
+            return arguments;
+        }
     }
 }

mustache-sharp/CompoundGenerator.cs

@@ -59,10 +59,10 @@ namespace Mustache
             }
         }
 
-        void IGenerator.GetText(KeyScope scope, TextWriter writer, object contextData)
+        void IGenerator.GetText(Scope keyScope, TextWriter writer, Scope contextScope)
         {
-            Dictionary<string, object> arguments = _arguments.GetArguments(scope);
+            Dictionary<string, object> arguments = _arguments.GetArguments(keyScope, contextScope);
-            IEnumerable<NestedContext> contexts = _definition.GetChildContext(writer, scope, arguments);
+            IEnumerable<NestedContext> contexts = _definition.GetChildContext(writer, keyScope, arguments, contextScope);
             List<IGenerator> generators;
             if (_definition.ShouldGeneratePrimaryGroup(arguments))
             {
@@ -80,7 +80,7 @@ namespace Mustache
             {
                 foreach (IGenerator generator in generators)
                 {
-                    generator.GetText(context.KeyScope ?? scope, context.Writer ?? writer, context.Data);
+                    generator.GetText(context.KeyScope ?? keyScope, context.Writer ?? writer, context.ContextScope);
                     if (context.WriterNeedsConsidated)
                     {
                         writer.Write(_definition.ConsolidateWriter(context.Writer ?? writer, arguments));

mustache-sharp/EachTagDefinition.cs

@@ -43,10 +43,14 @@ namespace Mustache
         /// Gets the context to use when building the inner text of the tag.
         /// </summary>
         /// <param name="writer">The text writer passed</param>
-        /// <param name="scope">The current scope.</param>
+        /// <param name="keyScope">The current scope.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
         /// <returns>The scope to use when building the inner text of the tag.</returns>
-        public override IEnumerable<NestedContext> GetChildContext(TextWriter writer, KeyScope scope, Dictionary<string, object> arguments)
+        public override IEnumerable<NestedContext> GetChildContext(
+            TextWriter writer, 
+            Scope keyScope, 
+            Dictionary<string, object> arguments,
+            Scope contextScope)
         {
             object value = arguments[collectionParameter];
             IEnumerable enumerable = value as IEnumerable;
@@ -57,7 +61,14 @@ namespace Mustache
             int index = 0;
             foreach (object item in enumerable)
             {
-                yield return new NestedContext() { KeyScope = scope.CreateChildScope(item), Writer = writer, Data = index };
+                NestedContext childContext = new NestedContext() 
+                { 
+                    KeyScope = keyScope.CreateChildScope(item), 
+                    Writer = writer, 
+                    ContextScope = contextScope.CreateChildScope(),
+                };
+                childContext.ContextScope.Set("index", index);
+                yield return childContext;
                 ++index;
             }
         }

mustache-sharp/FormatCompiler.cs

@@ -39,6 +39,8 @@ namespace Mustache
             _tagLookup.Add(withDefinition.Name, withDefinition);
             NewlineTagDefinition newlineDefinition = new NewlineTagDefinition();
             _tagLookup.Add(newlineDefinition.Name, newlineDefinition);
+            SetTagDefinition setDefinition = new SetTagDefinition();
+            _tagLookup.Add(setDefinition.Name, setDefinition);
         }
 
         /// <summary>
@@ -150,9 +152,11 @@ namespace Mustache
             foreach (TagParameter parameter in definition.Parameters)
             {
                 regexBuilder.Append(@"(\s+?");
-                regexBuilder.Append(@"(?<argument>");
+                regexBuilder.Append(@"(?<argument>(");
                 regexBuilder.Append(RegexHelper.CompoundKey);
-                regexBuilder.Append(@"))");
+                regexBuilder.Append("|@");
+                regexBuilder.Append(RegexHelper.Key);
+                regexBuilder.Append(@")))");
                 if (!parameter.IsRequired)
                 {
                     regexBuilder.Append("?");

mustache-sharp/Generator.cs

@@ -70,7 +70,7 @@ namespace Mustache
 
         private string render(IFormatProvider provider, object source)
         {
-            KeyScope scope = new KeyScope(source);
+            Scope scope = new Scope(source);
             foreach (EventHandler<KeyFoundEventArgs> handler in _foundHandlers)
             {
                 scope.KeyFound += handler;
@@ -80,7 +80,8 @@ namespace Mustache
                 scope.KeyNotFound += handler;
             }
             StringWriter writer = new StringWriter(provider);
-            _generator.GetText(scope, writer, null);
+            Scope contextScope = new Scope(new Dictionary<string, object>());
+            _generator.GetText(scope, writer, contextScope);
             return writer.ToString();
         }
     }

mustache-sharp/IGenerator.cs

@@ -11,10 +11,10 @@ namespace Mustache
         /// <summary>
         /// Generates the text when applying the format plan.
         /// </summary>
-        /// <param name="scope">The current lexical scope of the keys.</param>
+        /// <param name="keyScope">The current lexical scope of the keys.</param>
         /// <param name="writer">The text writer to send all text to.</param>
-        /// <param name="contextData">The data associated to the context.</param>
+        /// <param name="contextScope">The data associated to the context.</param>
         /// <returns>The generated text.</returns>
-        void GetText(KeyScope scope, TextWriter writer, object contextData);
+        void GetText(Scope keyScope, TextWriter writer, Scope contextScope);
     }
 }

mustache-sharp/IndexTagDefinition.cs

@@ -13,28 +13,23 @@ namespace Mustache
         /// Initializes a new instance of an IndexTagDefinition.
         /// </summary>
         public IndexTagDefinition()
-            : base("index")
+            : base("index", true)
         {
         }
 
-        /// <summary>
-        /// Gets whether the tag only exists within the scope of its parent.
-        /// </summary>
-        protected override bool GetIsContextSensitive()
-        {
-            return true;
-        }
-
         /// <summary>
         /// Gets the text to output.
         /// </summary>
         /// <param name="writer">The writer to write the output to.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
-        /// <param name="contextData">Extra data passed along with the context.</param>
+        /// <param name="contextScope">Extra data passed along with the context.</param>
-        public override void GetText(TextWriter writer, Dictionary<string, object> arguments, object contextData)
+        public override void GetText(TextWriter writer, Dictionary<string, object> arguments, Scope contextScope)
+        {
+            object index;
+            if (contextScope.TryFind("index", out index))
             {
-            int index = (int)contextData;
                 writer.Write(index);
             }
         }
+    }
 }

mustache-sharp/InlineGenerator.cs

@@ -5,7 +5,7 @@ using System.IO;
 namespace Mustache
 {
     /// <summary>
-    /// Generates the text for a tag that only exists on a single line.
+    /// Generates the text for a tag that is replaced with its generated text.
     /// </summary>
     internal sealed class InlineGenerator : IGenerator
     {
@@ -23,10 +23,18 @@ namespace Mustache
             _arguments = arguments;
         }
 
-        void IGenerator.GetText(KeyScope scope, TextWriter writer, object contextData)
+        void IGenerator.GetText(Scope scope, TextWriter writer, Scope context)
         {
-            Dictionary<string, object> arguments = _arguments.GetArguments(scope);
+            Dictionary<string, object> arguments;
-            _definition.GetText(writer, arguments, contextData);
+            if (_definition.IsSetter)
+            {
+                arguments = _arguments.GetArguments();   
+            }
+            else
+            {
+                arguments = _arguments.GetArguments(scope, context);
+            }            
+            _definition.GetText(writer, arguments, context);
         }
     }
 }

mustache-sharp/KeyGenerator.cs

@@ -42,7 +42,7 @@ namespace Mustache
             return formatBuilder.ToString();
         }
 
-        void IGenerator.GetText(KeyScope scope, TextWriter writer, object contextData)
+        void IGenerator.GetText(Scope scope, TextWriter writer, Scope context)
         {
             object value = scope.Find(_key);
             writer.Write(_format, value);

mustache-sharp/NestedContext.cs

@@ -19,36 +19,24 @@ namespace Mustache
         /// Gets or sets the writer to use when generating the child context.
         /// </summary>
         /// <remarks>Setting the writer to null will indicate that the tag's writer should be used.</remarks>
-        public TextWriter Writer
+        public TextWriter Writer { get; set; }
-        {
-            get;
-            set;
-        }
 
         /// <summary>
         /// Gets or sets whether the text sent to the returned writer needs to be added
         /// to the parent tag's writer. This should be false if the parent writer is
         /// being returned or is being wrapped.
         /// </summary>
-        public bool WriterNeedsConsidated
+        public bool WriterNeedsConsidated { get; set; }
-        {
-            get;
-            set;
-        }
 
         /// <summary>
-        /// Gets or sets the scope to use when generating the child context.
+        /// Gets or sets the key scope to use when generating the child context.
         /// </summary>
         /// <remarks>Setting the scope to null will indicate that the current scope should be used.</remarks>
-        public KeyScope KeyScope
+        public Scope KeyScope { get; set; }
-        {
-            get;
-            set;
-        }
 
         /// <summary>
         /// Gets or sets data associated with the context.
         /// </summary>
-        public object Data { get; set; }
+        public Scope ContextScope { get; set; }
     }
 }

mustache-sharp/NewlineTagDefinition.cs

@@ -22,8 +22,8 @@ namespace Mustache
         /// </summary>
         /// <param name="writer">The writer to write the output to.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
-        /// <param name="contextData">Extra data passed along with the context.</param>
+        /// <param name="context">Extra data passed along with the context.</param>
-        public override void GetText(TextWriter writer, Dictionary<string, object> arguments, object contextData)
+        public override void GetText(TextWriter writer, Dictionary<string, object> arguments, Scope context)
         {
             writer.Write(Environment.NewLine);
         }

mustache-sharp/RegexHelper.cs

@@ -8,7 +8,7 @@ namespace Mustache
     /// </summary>
     public static class RegexHelper
     {
-        private const string Key = @"[_\w][_\w\d]*";
+        internal const string Key = @"[_\w][_\w\d]*";
         internal const string CompoundKey = Key + @"(\." + Key + ")*";
 
         /// <summary>

mustache-sharp/Scope.cs

@@ -9,16 +9,16 @@ namespace Mustache
     /// <summary>
     /// Represents a scope of keys.
     /// </summary>
-    public sealed class KeyScope
+    public sealed class Scope
     {
         private readonly object _source;
-        private readonly KeyScope _parent;
+        private readonly Scope _parent;
 
         /// <summary>
         /// Initializes a new instance of a KeyScope.
         /// </summary>
         /// <param name="source">The object to search for keys in.</param>
-        internal KeyScope(object source)
+        internal Scope(object source)
             : this(source, null)
         {
         }
@@ -28,7 +28,7 @@ namespace Mustache
         /// </summary>
         /// <param name="source">The object to search for keys in.</param>
         /// <param name="parent">The parent scope to search in if the value is not found.</param>
-        internal KeyScope(object source, KeyScope parent)
+        internal Scope(object source, Scope parent)
         {
             _parent = parent;
             _source = source;
@@ -44,14 +44,23 @@ namespace Mustache
         /// </summary>
         public event EventHandler<KeyNotFoundEventArgs> KeyNotFound;
 
+        /// <summary>
+        /// Creates a child scope that searches for keys in a default dictionary of key/value pairs.
+        /// </summary>
+        /// <returns>The new child scope.</returns>
+        public Scope CreateChildScope()
+        {
+            return CreateChildScope(new Dictionary<string, object>());
+        }
+
         /// <summary>
         /// Creates a child scope that searches for keys in the given object.
         /// </summary>
         /// <param name="source">The object to search for keys in.</param>
         /// <returns>The new child scope.</returns>
-        public KeyScope CreateChildScope(object source)
+        public Scope CreateChildScope(object source)
         {
-            KeyScope scope = new KeyScope(source, this);
+            Scope scope = new Scope(source, this);
             scope.KeyFound = KeyFound;
             scope.KeyNotFound = KeyNotFound;
             return scope;
@@ -65,58 +74,45 @@ namespace Mustache
         /// <exception cref="System.Collections.Generic.KeyNotFoundException">A key with the given name could not be found.</exception>
         internal object Find(string name)
         {
-            string[] names = name.Split('.');
+            string member = null;
-            string member = names[0];
+            object value = null;
-            object nextLevel = _source;
+            if (tryFind(name, ref member, ref value))
-            if (member != "this")
             {
-                nextLevel = find(name, member);
+                onKeyFound(name, ref value);
+                return value;
             }
-            for (int index = 1; index < names.Length; ++index)
+            if (onKeyNotFound(name, member, ref value))
             {
-                IDictionary<string, object> context = toLookup(nextLevel);
+                return value;
-                member = names[index];
+            }
-                if (!context.TryGetValue(member, out nextLevel))
+            string message = String.Format(CultureInfo.CurrentCulture, Resources.KeyNotFound, member);
+            throw new KeyNotFoundException(message);
+        }
+
+        private void onKeyFound(string name, ref object value)
         {
-                    nextLevel = handleKeyNotFound(name, member);
-                }
-            }
             if (KeyFound != null)
             {
-                KeyFoundEventArgs args = new KeyFoundEventArgs(name, nextLevel);
+                KeyFoundEventArgs args = new KeyFoundEventArgs(name, value);
                 KeyFound(this, args);
-                nextLevel = args.Substitute;
+                value = args.Substitute;
             }
-            return nextLevel;
         }
 
-        private object find(string fullName, string memberName)
+        private bool onKeyNotFound(string name, string member, ref object value)
         {
-            IDictionary<string, object> lookup = toLookup(_source);
+            if (KeyNotFound == null)
-            if (lookup.ContainsKey(memberName))
             {
-                return lookup[memberName];
+                return false;
             }
-            if (_parent == null)
+            KeyNotFoundEventArgs args = new KeyNotFoundEventArgs(name, member);
-            {
-                return handleKeyNotFound(fullName, memberName);
-            }
-            return _parent.find(fullName, memberName);
-        }
-
-        private object handleKeyNotFound(string fullName, string memberName)
-        {
-            KeyNotFoundEventArgs args = new KeyNotFoundEventArgs(fullName, memberName);
-            if (KeyNotFound != null)
-            {
             KeyNotFound(this, args);
-            }
+            if (!args.Handled)
-            if (args.Handled)
             {
-                return args.Substitute;
+                return false;
             }
-            string message = String.Format(CultureInfo.CurrentCulture, Resources.KeyNotFound, memberName);
+            value = args.Substitute;
-            throw new KeyNotFoundException(message);
+            return true;
         }
 
         private static IDictionary<string, object> toLookup(object value)
@@ -128,5 +124,59 @@ namespace Mustache
             }
             return lookup;
         }
+
+        internal void Set(string key, object value)
+        {
+            IDictionary<string, object> lookup = toLookup(_source);
+            lookup[key] = value;
+        }
+
+        public bool TryFind(string name, out object value)
+        {
+            string member = null;
+            value = null;
+            return tryFind(name, ref member, ref value); 
+        }
+
+        private bool tryFind(string name, ref string member, ref object value)
+        {
+            string[] names = name.Split('.');
+            member = names[0];
+            value = _source;
+            if (member != "this")
+            {
+                if (!tryFindFirst(member, ref value))
+                {
+                    return false;
+                }
+            }
+            for (int index = 1; index < names.Length; ++index)
+            {
+                IDictionary<string, object> context = toLookup(value);
+                member = names[index];
+                if (!context.TryGetValue(member, out value))
+                {
+                    value = null;
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        private bool tryFindFirst(string member, ref object value)
+        {
+            IDictionary<string, object> lookup = toLookup(_source);
+            if (lookup.ContainsKey(member))
+            {
+                value = lookup[member];
+                return true;
+            }
+            if (_parent == null)
+            {
+                value = null;
+                return false;
+            }
+            return _parent.tryFindFirst(member, ref value);
+        }
     }
 }

mustache-sharp/SetTagDefinition.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace Mustache
+{
+    /// <summary>
+    /// Defines a tag that declares a named value in the current context.
+    /// </summary>
+    internal sealed class SetTagDefinition : InlineTagDefinition
+    {
+        private const string nameParameter = "name";
+        private static readonly TagParameter name = new TagParameter(nameParameter) { IsRequired = true };
+
+        /// <summary>
+        /// Initializes a new instance of an SetTagDefinition.
+        /// </summary>
+        public SetTagDefinition()
+            : base("set", true)
+        {
+        }
+
+        protected override bool GetIsSetter()
+        {
+            return true;
+        }
+
+        protected override IEnumerable<TagParameter> GetParameters()
+        {
+            return new TagParameter[] { name };
+        }
+
+        /// <summary>
+        /// Gets the text to output.
+        /// </summary>
+        /// <param name="writer">The writer to write the output to.</param>
+        /// <param name="arguments">The arguments passed to the tag.</param>
+        /// <param name="contextScope">Extra data passed along with the context.</param>
+        public override void GetText(TextWriter writer, Dictionary<string, object> arguments, Scope contextScope)
+        {
+            string name = (string)arguments[nameParameter];
+            // TODO - get the value for the variable
+            object value = null;
+            contextScope.Set(name, value);
+        }
+    }
+}

mustache-sharp/StaticGenerator.cs

@@ -27,7 +27,7 @@ namespace Mustache
             get { return value; }
         }
 
-        void IGenerator.GetText(KeyScope scope, TextWriter writer, object contextData)
+        void IGenerator.GetText(Scope scope, TextWriter writer, Scope context)
         {
             writer.Write(Value);
         }

mustache-sharp/TagDefinition.cs

@@ -44,6 +44,16 @@ namespace Mustache
             get { return _tagName; }
         }
 
+        internal bool IsSetter
+        {
+            get { return GetIsSetter(); }
+        }
+
+        protected virtual bool GetIsSetter()
+        {
+            return false;
+        }
+
         /// <summary>
         /// Gets whether the tag is limited to the parent tag's context.
         /// </summary>
@@ -139,12 +149,22 @@ namespace Mustache
         /// Gets the context to use when building the inner text of the tag.
         /// </summary>
         /// <param name="writer">The text writer passed</param>
-        /// <param name="scope">The current scope.</param>
+        /// <param name="keyScope">The current key scope.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
         /// <returns>The scope to use when building the inner text of the tag.</returns>
-        public virtual IEnumerable<NestedContext> GetChildContext(TextWriter writer, KeyScope scope, Dictionary<string, object> arguments)
+        public virtual IEnumerable<NestedContext> GetChildContext(
+            TextWriter writer, 
+            Scope keyScope, 
+            Dictionary<string, object> arguments,
+            Scope contextScope)
         {
-            yield return new NestedContext() { KeyScope = scope, Writer = writer };
+            NestedContext context = new NestedContext() 
+            { 
+                KeyScope = keyScope, 
+                Writer = writer,
+                ContextScope = contextScope.CreateChildScope()
+            };
+            yield return context;
         }
 
         /// <summary>
@@ -152,8 +172,8 @@ namespace Mustache
         /// </summary>
         /// <param name="writer">The text writer to write to.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
-        /// <param name="contextData">The data associated to the context.</param>
+        /// <param name="context">The data associated to the context.</param>
-        public virtual void GetText(TextWriter writer, Dictionary<string, object> arguments, object contextData)
+        public virtual void GetText(TextWriter writer, Dictionary<string, object> arguments, Scope context)
         {
         }
 

mustache-sharp/WithTagDefinition.cs

@@ -50,13 +50,23 @@ namespace Mustache
         /// Gets the context to use when building the inner text of the tag.
         /// </summary>
         /// <param name="writer">The text writer passed</param>
-        /// <param name="scope">The current scope.</param>
+        /// <param name="keyScope">The current key scope.</param>
         /// <param name="arguments">The arguments passed to the tag.</param>
         /// <returns>The scope to use when building the inner text of the tag.</returns>
-        public override IEnumerable<NestedContext> GetChildContext(TextWriter writer, KeyScope scope, Dictionary<string, object> arguments)
+        public override IEnumerable<NestedContext> GetChildContext(
+            TextWriter writer, 
+            Scope keyScope, 
+            Dictionary<string, object> arguments,
+            Scope contextScope)
         {
-            object context = arguments[contextParameter];
+            object contextSource = arguments[contextParameter];
-            yield return new NestedContext() { KeyScope = scope.CreateChildScope(context), Writer = writer };
+            NestedContext context = new NestedContext() 
+            { 
+                KeyScope = keyScope.CreateChildScope(contextSource), 
+                Writer = writer,
+                ContextScope = contextScope.CreateChildScope()
+            };
+            yield return context;
         }
     }
 }

mustache-sharp/mustache-sharp.csproj

@@ -40,6 +40,7 @@
     <Compile Include="ContentTagDefinition.cs" />
     <Compile Include="Context.cs" />
     <Compile Include="ContextParameter.cs" />
+    <Compile Include="SetTagDefinition.cs" />
     <Compile Include="NewlineTagDefinition.cs" />
     <Compile Include="IndexTagDefinition.cs" />
     <Compile Include="KeyFoundEventArgs.cs" />
@@ -68,8 +69,8 @@
     <Compile Include="StaticGenerator.cs" />
     <Compile Include="TagDefinition.cs" />
     <Compile Include="TagParameter.cs" />
-    <Compile Include="KeyScope.cs" />
+    <Compile Include="Scope.cs" />
-    <Compile Include="WithGenerator.cs" />
+    <Compile Include="WithTagDefinition.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="Properties\Resources.resx">