PreprocessorGuards.cs

// Copyright 2005-2015 Giacomo Stelluti Scala & Contributors. All rights reserved. See License.md in the project root for license information.

using System;
using System.Collections.Generic;
using System.Linq;

namespace CommandLine.Core
{
    static class PreprocessorGuards
    {
        public static IEnumerable<Func<IEnumerable<string>, IEnumerable<Error>>>
            Lookup(StringComparer nameComparer, bool autoHelp, bool autoVersion, OptionsParseMode optionsParseMode)
        {
            var list = new List<Func<IEnumerable<string>, IEnumerable<Error>>>();
            if (autoHelp)
                list.Add(HelpCommand(nameComparer, optionsParseMode));
            if (autoVersion)
                list.Add(VersionCommand(nameComparer, optionsParseMode));
            return list;
        }
        public static Func<IEnumerable<string>, IEnumerable<Error>> HelpCommand(StringComparer nameComparer, OptionsParseMode optionsParseMode)
        {
            return
                arguments =>
                    optionsParseMode != OptionsParseMode.SingleDashOnly && nameComparer.Equals("--help", arguments.First())
                    || optionsParseMode != OptionsParseMode.Default && nameComparer.Equals("-help", arguments.First())
                        ? new Error[] { new HelpRequestedError() }
                        : Enumerable.Empty<Error>();
        }

        public static Func<IEnumerable<string>, IEnumerable<Error>> VersionCommand(StringComparer nameComparer, OptionsParseMode optionsParseMode)
        {
            return
                arguments =>
                    optionsParseMode != OptionsParseMode.SingleDashOnly && nameComparer.Equals("--version", arguments.First())
                    || optionsParseMode != OptionsParseMode.Default && nameComparer.Equals("-version", arguments.First())
                        ? new Error[] { new VersionRequestedError() }
                        : Enumerable.Empty<Error>();
        }
    }
}