/DLR_Main/Runtime/Microsoft.Scripting.Core/Ast/ListInitExpression.cs

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 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A 

 * copy of the license can be found in the License.html file at the root of this distribution. If 

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 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 

 * by the terms of the Apache License, Version 2.0.

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 * You must not remove this notice, or any other, from this software.

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using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.Diagnostics;

using System.Dynamic.Utils;

using System.Reflection;

using System.Runtime.CompilerServices;



#if SILVERLIGHT

using System.Core;

#endif



#if CLR2

namespace Microsoft.Scripting.Ast {

#else

namespace System.Linq.Expressions {

#endif

    /// <summary>

    /// Represents a constructor call that has a collection initializer.

    /// </summary>

    /// <remarks>

    /// Use the <see cref="M:ListInit"/> factory methods to create a ListInitExpression. 

    /// The value of the NodeType property of a ListInitExpression is ListInit. 

    /// </remarks>

#if !SILVERLIGHT

    [DebuggerTypeProxy(typeof(Expression.ListInitExpressionProxy))]

#endif

    public sealed class ListInitExpression : Expression {

        private readonly NewExpression _newExpression;

        private readonly ReadOnlyCollection<ElementInit> _initializers;



        internal ListInitExpression(NewExpression newExpression, ReadOnlyCollection<ElementInit> initializers) {

            _newExpression = newExpression;

            _initializers = initializers;

        }



        /// <summary>

        /// Returns the node type of this <see cref="Expression"/>. (Inherited from <see cref="Expression" />.)

        /// </summary>

        /// <returns>The <see cref="ExpressionType"/> that represents this expression.</returns>

        public sealed override ExpressionType NodeType {

            get { return ExpressionType.ListInit; }

        }



        /// <summary>

        /// Gets the static type of the expression that this <see cref="Expression" /> represents. (Inherited from <see cref="Expression"/>.)

        /// </summary>

        /// <returns>The <see cref="Type"/> that represents the static type of the expression.</returns>

        public sealed override Type Type {

            get { return _newExpression.Type; }

        }



        /// <summary>

        /// Gets a value that indicates whether the expression tree node can be reduced. 

        /// </summary>

        public override bool CanReduce {

            get {

                return true;

            }

        }



        /// <summary>

        /// Gets the expression that contains a call to the constructor of a collection type. 

        /// </summary>

        public NewExpression NewExpression {

            get { return _newExpression; }

        }



        /// <summary>

        /// Gets the element initializers that are used to initialize a collection. 

        /// </summary>

        public ReadOnlyCollection<ElementInit> Initializers {

            get { return _initializers; }

        }



        /// <summary>

        /// Dispatches to the specific visit method for this node type.

        /// </summary>

        protected internal override Expression Accept(ExpressionVisitor visitor) {

            return visitor.VisitListInit(this);

        }



        /// <summary>

        /// Reduces the binary expression node to a simpler expression. 

        /// If CanReduce returns true, this should return a valid expression.

        /// This method is allowed to return another node which itself 

        /// must be reduced.

        /// </summary>

        /// <returns>The reduced expression.</returns>

        public override Expression Reduce() {

            return MemberInitExpression.ReduceListInit(_newExpression, _initializers, true);

        }



        /// <summary>

        /// Creates a new expression that is like this one, but using the

        /// supplied children. If all of the children are the same, it will

        /// return this expression.

        /// </summary>

        /// <param name="newExpression">The <see cref="NewExpression" /> property of the result.</param>

        /// <param name="initializers">The <see cref="Initializers" /> property of the result.</param>

        /// <returns>This expression if no children changed, or an expression with the updated children.</returns>

        public ListInitExpression Update(NewExpression newExpression, IEnumerable<ElementInit> initializers) {

            if (newExpression == NewExpression && initializers == Initializers) {

                return this;

            }

            return Expression.ListInit(newExpression, initializers);

        }

    }





    public partial class Expression {

        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses a method named "Add" to add elements to a collection.

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="initializers">An array of <see cref="Expression"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>

        /// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>

        public static ListInitExpression ListInit(NewExpression newExpression, params Expression[] initializers) {

            ContractUtils.RequiresNotNull(newExpression, "newExpression");

            ContractUtils.RequiresNotNull(initializers, "initializers");

            return ListInit(newExpression, initializers as IEnumerable<Expression>);

        }



        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses a method named "Add" to add elements to a collection.

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>

        /// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>

        public static ListInitExpression ListInit(NewExpression newExpression, IEnumerable<Expression> initializers) {

            ContractUtils.RequiresNotNull(newExpression, "newExpression");

            ContractUtils.RequiresNotNull(initializers, "initializers");



            var initializerlist = initializers.ToReadOnly();

            if (initializerlist.Count == 0) {

                throw Error.ListInitializerWithZeroMembers();

            }



            MethodInfo addMethod = FindMethod(newExpression.Type, "Add", null, new Expression[] { initializerlist[0] }, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);

            return ListInit(newExpression, addMethod, initializers);

        }



        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses a specified method to add elements to a collection. 

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="addMethod">A <see cref="MethodInfo"/> that represents an instance method named "Add" (case insensitive), that adds an element to a collection. </param>

        /// <param name="initializers">An array of <see cref="Expression"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>

        /// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>

        public static ListInitExpression ListInit(NewExpression newExpression, MethodInfo addMethod, params Expression[] initializers) {

            if (addMethod == null) {

                return ListInit(newExpression, initializers as IEnumerable<Expression>);

            }

            ContractUtils.RequiresNotNull(newExpression, "newExpression");

            ContractUtils.RequiresNotNull(initializers, "initializers");

            return ListInit(newExpression, addMethod, initializers as IEnumerable<Expression>);

        }



        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses a specified method to add elements to a collection. 

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="addMethod">A <see cref="MethodInfo"/> that represents an instance method named "Add" (case insensitive), that adds an element to a collection. </param>

        /// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="Expression"/> objects to use to populate the Initializers collection.</param>

        /// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>

        public static ListInitExpression ListInit(NewExpression newExpression, MethodInfo addMethod, IEnumerable<Expression> initializers) {

            if (addMethod == null) {

                return ListInit(newExpression, initializers);

            }

            ContractUtils.RequiresNotNull(newExpression, "newExpression");

            ContractUtils.RequiresNotNull(initializers, "initializers");



            var initializerlist = initializers.ToReadOnly();

            if (initializerlist.Count == 0) {

                throw Error.ListInitializerWithZeroMembers();

            }

            ElementInit[] initList = new ElementInit[initializerlist.Count];

            for (int i = 0; i < initializerlist.Count; i++) {

                initList[i] = ElementInit(addMethod, initializerlist[i]);

            }

            return ListInit(newExpression, new TrueReadOnlyCollection<ElementInit>(initList));

        }



        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses specified <see cref="M:ElementInit"/> objects to initialize a collection. 

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="initializers">An array that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>

        /// <returns>

        /// A <see cref="ListInitExpression"/> that has the <see cref="P:Expressions.NodeType"/> property equal to ListInit 

        /// and the <see cref="P:ListInitExpression.NewExpression"/> and <see cref="P:ListInitExpression.Initializers"/> properties set to the specified values.

        /// </returns>

        /// <remarks>

        /// The <see cref="P:Expressions.Type"/> property of <paramref name="newExpression"/> must represent a type that implements <see cref="System.Collections.IEnumerable"/>. 

        /// The <see cref="P:Expressions.Type"/> property of the resulting <see cref="ListInitExpression"/> is equal to newExpression.Type. 

        /// </remarks>

        public static ListInitExpression ListInit(NewExpression newExpression, params ElementInit[] initializers) {

            return ListInit(newExpression, (IEnumerable<ElementInit>)initializers);

        }



        /// <summary>

        /// Creates a <see cref="ListInitExpression"/> that uses specified <see cref="M:ElementInit"/> objects to initialize a collection. 

        /// </summary>

        /// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>

        /// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>

        /// <returns>An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</returns>

        /// <remarks>

        /// The <see cref="P:Expressions.Type"/> property of <paramref name="newExpression"/> must represent a type that implements <see cref="System.Collections.IEnumerable"/>. 

        /// The <see cref="P:Expressions.Type"/> property of the resulting <see cref="ListInitExpression"/> is equal to newExpression.Type. 

        /// </remarks>

        public static ListInitExpression ListInit(NewExpression newExpression, IEnumerable<ElementInit> initializers) {

            ContractUtils.RequiresNotNull(newExpression, "newExpression");

            ContractUtils.RequiresNotNull(initializers, "initializers");

            var initializerlist = initializers.ToReadOnly();

            if (initializerlist.Count == 0) {

                throw Error.ListInitializerWithZeroMembers();

            }

            ValidateListInitArgs(newExpression.Type, initializerlist);

            return new ListInitExpression(newExpression, initializerlist);

        }

    }

}