/* ****************************************************************************
*
* 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
* you cannot locate the Apache License, Version 2.0, please send an email to
* 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.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Dynamic.Utils;
using System.Runtime.CompilerServices;
#if CLR2
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
///
/// An expression that provides runtime read/write access to variables.
/// Needed to implement "eval" in some dynamic languages.
/// Evaluates to an instance of when executed.
///
#if !SILVERLIGHT
[DebuggerTypeProxy(typeof(Expression.RuntimeVariablesExpressionProxy))]
#endif
public sealed class RuntimeVariablesExpression : Expression {
private readonly ReadOnlyCollection _variables;
internal RuntimeVariablesExpression(ReadOnlyCollection variables) {
_variables = variables;
}
///
/// Gets the static type of the expression that this represents.
///
/// The that represents the static type of the expression.
public sealed override Type Type {
get { return typeof(IRuntimeVariables); }
}
///
/// Returns the node type of this Expression. Extension nodes should return
/// ExpressionType.Extension when overriding this method.
///
/// The of the expression.
public sealed override ExpressionType NodeType {
get { return ExpressionType.RuntimeVariables; }
}
///
/// The variables or parameters to which to provide runtime access.
///
public ReadOnlyCollection Variables {
get { return _variables; }
}
///
/// Dispatches to the specific visit method for this node type.
///
protected internal override Expression Accept(ExpressionVisitor visitor) {
return visitor.VisitRuntimeVariables(this);
}
///
/// 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.
///
/// The property of the result.
/// This expression if no children changed, or an expression with the updated children.
public RuntimeVariablesExpression Update(IEnumerable variables) {
if (variables == Variables) {
return this;
}
return Expression.RuntimeVariables(variables);
}
}
public partial class Expression {
///
/// Creates an instance of .
///
/// An array of objects to use to populate the collection.
/// An instance of that has the property equal to and the property set to the specified value.
public static RuntimeVariablesExpression RuntimeVariables(params ParameterExpression[] variables) {
return RuntimeVariables((IEnumerable)variables);
}
///
/// Creates an instance of .
///
/// A collection of objects to use to populate the collection.
/// An instance of that has the property equal to and the property set to the specified value.
public static RuntimeVariablesExpression RuntimeVariables(IEnumerable variables) {
ContractUtils.RequiresNotNull(variables, "variables");
var vars = variables.ToReadOnly();
for (int i = 0; i < vars.Count; i++) {
Expression v = vars[i];
if (v == null) {
throw new ArgumentNullException("variables[" + i + "]");
}
}
return new RuntimeVariablesExpression(vars);
}
}
}