// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
 
namespace Microsoft.ML.CommandLine
{
    /// <summary>
    /// Used to control parsing of command line arguments.
    /// </summary>
    [Flags]
    [BestFriend]
    internal enum ArgumentType
    {
        /// <summary>
        /// Indicates that this field is required. An error will be displayed
        /// if it is not present when parsing arguments.
        /// </summary>
        Required = 0x01,
 
        /// <summary>
        /// Only valid in conjunction with Multiple.
        /// Duplicate values will result in an error.
        /// </summary>
        Unique = 0x02,
 
        /// <summary>
        /// Indicates that the argument may be specified more than once.
        /// Only valid if the argument is a collection
        /// </summary>
        Multiple = 0x04,
 
        /// <summary>
        /// The default type for non-collection arguments.
        /// The argument is not required, but an error will be reported if it is specified more than once.
        /// </summary>
        AtMostOnce = 0x00,
 
        /// <summary>
        /// For non-collection arguments, when the argument is specified more than
        /// once no error is reported and the value of the argument is the last
        /// value which occurs in the argument list.
        /// </summary>
        LastOccurrenceWins = Multiple,
 
        /// <summary>
        /// The default type for collection arguments.
        /// The argument is permitted to occur multiple times, but duplicate
        /// values will cause an error to be reported.
        /// </summary>
        MultipleUnique = Multiple | Unique,
    }
}