ParamDictionaryAttribute.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information.

#nullable enable

using System;

namespace Microsoft.Scripting {
    /// <summary>
    /// This attribute is used to mark a parameter that can accept any keyword arguments that
    /// are not bound to normal parameters.  The extra keyword arguments will be
    /// passed in a dictionary which is created for the call.
    /// 
    /// Most languages which support params dictionaries will support the following types:
    /// <code>
    ///     IReadOnlyDictionary&lt;string, anything&gt;<br/>
    ///     IReadOnlyDictionary&lt;object, anything&gt;<br/>
    ///     IDictionary&lt;string, anything&gt;<br/>
    ///     IDictionary&lt;object, anything&gt;<br/>
    ///     Dictionary&lt;string, anything&gt;<br/>
    ///     Dictionary&lt;object, anything&gt;<br/>
    ///     IDictionary
    /// </code>
    /// 
    /// For languages which don't have language level support the user will be required to
    /// create and populate the dictionary by hand.
    /// 
    /// This attribute is the dictionary equivalent of the System.ParamArrayAttribute.
    /// </summary>
    /// <example>
    /// public static void KeywordArgFunction([ParamDictionary]IDictionary&lt;string, object&gt; dict) {
    ///     foreach (var v in dict) {
    ///         Console.WriteLine("Key: {0} Value: {1}", v.Key, v.Value);
    ///     }
    /// }
    /// 
    /// Called from Python:
    /// 
    /// KeywordArgFunction(a = 2, b = "abc")
    /// 
    /// will print:
    ///     Key: a Value = 2
    ///     Key: b Value = abc
    /// </example>
    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
    public sealed class ParamDictionaryAttribute : Attribute {
    }
}