Some more LINQ work. Added MongoExpression and related types.

Author: rstam

Driver/Driver.csproj

@@ -180,16 +180,23 @@
     <Compile Include="Internal\MongoReplyMessage.cs" />
     <Compile Include="Internal\MongoUpdateMessage.cs" />
     <Compile Include="Internal\ReplicaSetConnector.cs" />
-    <Compile Include="Linq\Nominator.cs" />
-    <Compile Include="Linq\PartialEvaluator.cs" />
-    <Compile Include="Linq\ExpressionPrettyPrinter.cs" />
-    <Compile Include="Linq\ExpressionVisitor.cs" />
-    <Compile Include="Linq\TranslatedFindQuery.cs" />
+    <Compile Include="Linq\Expressions\MongoCollectionExpression.cs" />
+    <Compile Include="Linq\Expressions\MongoExpression.cs" />
+    <Compile Include="Linq\Expressions\MongoExpressionType.cs" />
+    <Compile Include="Linq\Expressions\MongoExpressionVisitor.cs" />
+    <Compile Include="Linq\Expressions\MongoFieldExpression.cs" />
+    <Compile Include="Linq\Expressions\MongoProjectionExpression.cs" />
+    <Compile Include="Linq\Expressions\MongoSelectExpression.cs" />
+    <Compile Include="Linq\Translators\Nominator.cs" />
+    <Compile Include="Linq\Translators\PartialEvaluator.cs" />
+    <Compile Include="Linq\Expressions\ExpressionPrettyPrinter.cs" />
+    <Compile Include="Linq\Expressions\ExpressionVisitor.cs" />
+    <Compile Include="Linq\Translators\TranslatedFindQuery.cs" />
     <Compile Include="Linq\ExtensionMethods.cs" />
     <Compile Include="Linq\MongoQueryable.cs" />
     <Compile Include="Linq\MongoQueryProvider.cs" />
-    <Compile Include="Linq\MongoQueryTranslator.cs" />
-    <Compile Include="Linq\TranslatedQuery.cs" />
+    <Compile Include="Linq\Translators\MongoQueryTranslator.cs" />
+    <Compile Include="Linq\Translators\TranslatedQuery.cs" />
     <Compile Include="Linq\TypeSystem.cs" />
     <Compile Include="MongoUtils.cs" />
     <Compile Include="MongoDefaults.cs" />

Driver/Linq/ExpressionPrettyPrinter.cs renamed to Driver/Linq/Expressions/ExpressionPrettyPrinter.cs

@@ -0,0 +1,60 @@
+/* Copyright 2010-2012 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+namespace MongoDB.Driver.Linq
+{
+    /// <summary>
+    /// A MongoExpression that represents a collection.
+    /// </summary>
+    public class MongoCollectionExpression : MongoExpression
+    {
+        private MongoCollection _collection;
+        private Type _documentType;
+
+        /// <summary>
+        /// Initializes an instance of the MongoCollectionExpression class.
+        /// </summary>
+        /// <param name="collection">The collection referenced.</param>
+        /// <param name="documentType">The document type.</param>
+        public MongoCollectionExpression(MongoCollection collection, Type documentType)
+            : base(MongoExpressionType.Collection, typeof(void))
+        {
+            _collection = collection;
+            _documentType = documentType;
+        }
+
+        /// <summary>
+        /// Gets the collection.
+        /// </summary>
+        public MongoCollection Collection
+        {
+            get { return _collection; }
+        }
+
+        /// <summary>
+        /// Gets the document type.
+        /// </summary>
+        public Type DocumentType
+        {
+            get { return _documentType; }
+        }
+    }
+}

Driver/Linq/ExpressionVisitor.cs renamed to Driver/Linq/Expressions/ExpressionVisitor.cs

@@ -0,0 +1,39 @@
+/* Copyright 2010-2012 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+namespace MongoDB.Driver.Linq
+{
+    /// <summary>
+    /// A custom Expression that represents some Mongo LINQ construct (see derived classes).
+    /// </summary>
+    public abstract class MongoExpression : Expression
+    {
+        /// <summary>
+        /// Initializes an instance of the MongoExpression class.
+        /// </summary>
+        /// <param name="nodeType">The MongoExpressionType of this node.</param>
+        /// <param name="type">The Type of this MongoExpression.</param>
+        protected MongoExpression(MongoExpressionType nodeType, Type type)
+            : base((ExpressionType)nodeType, type)
+        {
+        }
+    }
+}

Driver/Linq/Expressions/MongoCollectionExpression.cs

@@ -0,0 +1,51 @@
+/* Copyright 2010-2012 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+namespace MongoDB.Driver.Linq
+{
+    /// <summary>
+    /// Represents additional Expression node types for MongoExpression nodes in an expression tree.
+    /// </summary>
+    public enum MongoExpressionType
+    {
+        // note: make sure these values don't conflict with ExpressionType
+
+        /// <summary>
+        /// An operation that references a MongoDB collection.
+        /// </summary>
+        Collection = 1000,
+
+        /// <summary>
+        /// An operation that references a MongoDB field.
+        /// </summary>
+        Field,
+
+        /// <summary>
+        /// A select operation against MongoDB.
+        /// </summary>
+        Select,
+
+        /// <summary>
+        /// A projection operation against MongoDB.
+        /// </summary>
+        Projection
+    }
+}

Driver/Linq/Expressions/MongoExpression.cs

@@ -0,0 +1,103 @@
+/* Copyright 2010-2012 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+namespace MongoDB.Driver.Linq
+{
+    /// <summary>
+    /// A base class for classes that visit MongoExpressions.
+    /// </summary>
+    public abstract class MongoExpressionVisitor : ExpressionVisitor
+    {
+        /// <summary>
+        /// Initializes an instance of the MongoExpressionVisitor class.
+        /// </summary>
+        protected MongoExpressionVisitor()
+        {
+        }
+
+        /// <summary>
+        /// Visits an Expression (which might be a MongoExpression).
+        /// </summary>
+        /// <param name="node">The expression to visit.</param>
+        /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+        protected override Expression Visit(Expression node)
+        {
+            if (node == null)
+            {
+                return null;
+            }
+
+            switch ((MongoExpressionType)node.NodeType)
+            {
+                case MongoExpressionType.Collection:
+                    return VisitCollection((MongoCollectionExpression)node);
+                case MongoExpressionType.Field:
+                    return VisitField((MongoFieldExpression)node);
+                case MongoExpressionType.Projection:
+                    return VisitProjection((MongoProjectionExpression)node);
+                case MongoExpressionType.Select:
+                    return VisitSelect((MongoSelectExpression)node);
+                default:
+                    return base.Visit(node);
+            }
+        }
+
+        /// <summary>
+        /// Visits a MongoCollectionExpression.
+        /// </summary>
+        /// <param name="node">The expression to visit.</param>
+        /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+        protected virtual Expression VisitCollection(MongoCollectionExpression node)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Visits a MongoFieldExpression.
+        /// </summary>
+        /// <param name="node">The expression to visit.</param>
+        /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+        protected virtual Expression VisitField(MongoFieldExpression node)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Visits a MongoProjectionExpression.
+        /// </summary>
+        /// <param name="node">The expression to visit.</param>
+        /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+        protected virtual Expression VisitProjection(MongoProjectionExpression node)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// Visits a MongoSelectExpression.
+        /// </summary>
+        /// <param name="node">The expression to visit.</param>
+        /// <returns>The modified expression, if it or any subexpression was modified; otherwise, returns the original expression.</returns>
+        protected virtual Expression VisitSelect(MongoSelectExpression node)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

Driver/Linq/Expressions/MongoExpressionType.cs

@@ -0,0 +1,73 @@
+/* Copyright 2010-2012 10gen Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+
+using MongoDB.Bson.Serialization;
+
+namespace MongoDB.Driver.Linq
+{
+    /// <summary>
+    /// A MongoExpression that represents a field reference.
+    /// </summary>
+    public class MongoFieldExpression : MongoExpression
+    {
+        private Expression _expression;
+        private string _name;
+        private BsonMemberMap _memberMap;
+
+        /// <summary>
+        /// Initializes an instance of the MongoFieldExpression class.
+        /// </summary>
+        /// <param name="expression">The expression that references the field.</param>
+        /// <param name="name">The name of the referenced field.</param>
+        /// <param name="memberMap">The BsonMemberMap of the referenced field.</param>
+        public MongoFieldExpression(Expression expression, string name, BsonMemberMap memberMap)
+            : base(MongoExpressionType.Field, expression.Type)
+        {
+            _expression = expression;
+            _name = name;
+            _memberMap = memberMap;
+        }
+
+        /// <summary>
+        /// Gets the expression that references the field.
+        /// </summary>
+        public Expression Expression
+        {
+            get { return _expression; }
+        }
+
+        /// <summary>
+        /// Gets the BsonMemberMap of the referenced field.
+        /// </summary>
+        public BsonMemberMap MemberMap
+        {
+            get { return _memberMap; }
+        }
+
+        /// <summary>
+        /// Gets the name of the referenced field.
+        /// </summary>
+        public string Name
+        {
+            get { return _name; }
+        }
+    }
+}