Remove CompletionDelegate, CompletionSourceList and DirectiveCollection

src/System.CommandLine.Benchmarks/CommandLine/Perf_Parser_ParseResult.cs

@@ -43,7 +43,7 @@ public IEnumerable<object> GenerateTestParseResults()
 
         [Benchmark]
         [ArgumentsSource(nameof(GenerateTestInputs))]
-        public DirectiveCollection ParseResult_Directives(string input)
+        public IReadOnlyDictionary<string, IReadOnlyList<string>> ParseResult_Directives(string input)
             => _testParser.Parse(input).Directives;
 
         [Benchmark]

src/System.CommandLine.Hosting/DirectiveConfigurationExtensions.cs

@@ -16,7 +16,7 @@ public static IConfigurationBuilder AddCommandLineDirectives(
             if (name is null)
                 throw new ArgumentNullException(nameof(name));
 
-            if (!commandline.Directives.TryGetValues(name, out var directives))
+            if (!commandline.Directives.TryGetValue(name, out var directives))
                 return config;
 
             var kvpSeparator = new[] { '=' };

src/System.CommandLine.Rendering/CommandLineBuilderExtensions.cs

@@ -28,7 +28,7 @@ public static CommandLineBuilder UseAnsiTerminalWhenAvailable(
         internal static bool PreferVirtualTerminal(
             this BindingContext context)
         {
-            if (context.ParseResult.Directives.TryGetValues(
+            if (context.ParseResult.Directives.TryGetValue(
                 "enable-vt",
                 out var trueOrFalse))
             {
@@ -45,7 +45,7 @@ internal static bool PreferVirtualTerminal(
 
         public static OutputMode OutputMode(this BindingContext context)
         {
-            if (context.ParseResult.Directives.TryGetValues(
+            if (context.ParseResult.Directives.TryGetValue(
                     "output",
                     out var modeString) &&
                 Enum.TryParse<OutputMode>(

src/System.CommandLine.Tests/DirectiveTests.cs

@@ -28,7 +28,7 @@ public void Raw_tokens_still_hold_directives()
 
             var result = option.Parse("[parse] -y");
 
-            result.Directives.Contains("parse").Should().BeTrue();
+            result.Directives.ContainsKey("parse").Should().BeTrue();
             result.Tokens.Should().Contain(t => t.Value == "[parse]");
         }
 
@@ -39,7 +39,7 @@ public void Directives_should_parse_into_the_directives_collection()
 
             var result = option.Parse("[parse] -y");
 
-            result.Directives.Contains("parse").Should().BeTrue();
+            result.Directives.ContainsKey("parse").Should().BeTrue();
         }
 
         [Fact]
@@ -49,8 +49,8 @@ public void Multiple_directives_are_allowed()
 
             var result = option.Parse("[parse] [suggest] -y");
 
-            result.Directives.Contains("parse").Should().BeTrue();
-            result.Directives.Contains("suggest").Should().BeTrue();
+            result.Directives.ContainsKey("parse").Should().BeTrue();
+            result.Directives.ContainsKey("suggest").Should().BeTrue();
         }
 
         [Fact]
@@ -76,7 +76,7 @@ public void Directives_can_have_a_value_which_is_everything_after_the_first_colo
 
             var result = option.Parse($"{directive} -y");
 
-            result.Directives.TryGetValues(expectedKey, out var values).Should().BeTrue();
+            result.Directives.TryGetValue(expectedKey, out var values).Should().BeTrue();
             values.Should().BeEquivalentTo(expectedValue);
         }
 
@@ -87,7 +87,7 @@ public void Directives_without_a_value_specified_have_a_value_of_empty_string()
 
             var result = option.Parse("[parse] -y");
 
-            result.Directives.TryGetValues("parse", out var values).Should().BeTrue();
+            result.Directives.TryGetValue("parse", out var values).Should().BeTrue();
             values.Should().BeEmpty();
         }
 
@@ -124,7 +124,7 @@ public void When_a_directive_is_specified_more_than_once_then_its_values_are_agg
 
             var result = option.Parse("[directive:one] [directive:two] -a");
 
-            result.Directives.TryGetValues("directive", out var values).Should().BeTrue();
+            result.Directives.TryGetValue("directive", out var values).Should().BeTrue();
             values.Should().BeEquivalentTo("one", "two");
         }
 

src/System.CommandLine.Tests/UseHelpTests.cs

@@ -301,7 +301,7 @@ public void Help_sections_can_be_replaced()
 
             console.Out.ToString().Should().Be($"one{NewLine}{NewLine}two{NewLine}{NewLine}three{NewLine}{NewLine}{NewLine}");
 
-            IEnumerable<HelpSectionDelegate> CustomLayout(HelpContext _)
+            IEnumerable<Action<HelpContext>> CustomLayout(HelpContext _)
             {
                 yield return ctx => ctx.Output.WriteLine("one");
                 yield return ctx => ctx.Output.WriteLine("two");
@@ -327,7 +327,7 @@ public void Help_sections_can_be_supplemented()
 
             output.Should().Be(expected);
 
-            IEnumerable<HelpSectionDelegate> CustomLayout(HelpContext _)
+            IEnumerable<Action<HelpContext>> CustomLayout(HelpContext _)
             {
                 yield return ctx => ctx.Output.WriteLine("first");
 
@@ -358,7 +358,7 @@ public void Layout_can_be_composed_dynamically_based_on_context()
                                     .CustomizeLayout(c =>
                                                          c.Command == commandWithTypicalHelp
                                                              ? HelpBuilder.Default.GetLayout()
-                                                             : new HelpSectionDelegate[]
+                                                             : new Action<HelpContext>[]
                                                                  {
                                                                      c => c.Output.WriteLine("Custom layout!")
                                                                  }
@@ -417,7 +417,7 @@ public void Help_customized_sections_can_be_wrapped()
             string result = console.Out.ToString();
             result.Should().Be($"  123  123{NewLine}  456  456{NewLine}  78   789{NewLine}       0{NewLine}{NewLine}{NewLine}");
 
-            IEnumerable<HelpSectionDelegate> CustomLayout(HelpContext _)
+            IEnumerable<Action<HelpContext>> CustomLayout(HelpContext _)
             {
                 yield return ctx => ctx.HelpBuilder.WriteColumns(new[] { new TwoColumnHelpRow("12345678", "1234567890") }, ctx);
             }

src/System.CommandLine/Argument.cs

@@ -17,8 +17,8 @@ public abstract class Argument : Symbol, IValueDescriptor
         private Func<ArgumentResult, object?>? _defaultValueFactory;
         private ArgumentArity _arity;
         private TryConvertArgument? _convertArguments;
-        private CompletionSourceList? _completions = null;
-        private List<ValidateSymbolResult<ArgumentResult>>? _validators = null;
+        private List<ICompletionSource>? _completions = null;
+        private List<Action<ArgumentResult>>? _validators = null;
 
         /// <summary>
         /// Initializes a new instance of the Argument class.
@@ -72,10 +72,10 @@ internal TryConvertArgument? ConvertArguments
         }
 
         /// <summary>
-        /// Gets the list of completion sources for the argument.
+        /// Gets the collection of completion sources for the argument.
         /// </summary>
-        public CompletionSourceList Completions =>
-            _completions ??= new CompletionSourceList
+        public ICollection<ICompletionSource> Completions =>
+            _completions ??= new ()
             {
                 CompletionSource.ForType(ValueType)
             };
@@ -104,14 +104,14 @@ private protected override string DefaultName
             }
         }
 
-        internal List<ValidateSymbolResult<ArgumentResult>> Validators => _validators ??= new ();
+        internal List<Action<ArgumentResult>> Validators => _validators ??= new ();
 
         /// <summary>
-        /// Adds a custom <see cref="ValidateSymbolResult{ArgumentResult}"/> to the argument. Validators can be used
+        /// Adds a custom validator to the argument. Validators can be used
         /// to provide custom errors based on user input.
         /// </summary>
-        /// <param name="validate">The delegate to validate the parsed argument.</param>
-        public void AddValidator(ValidateSymbolResult<ArgumentResult> validate) => Validators.Add(validate);
+        /// <param name="validate">The action to validate the parsed argument.</param>
+        public void AddValidator(Action<ArgumentResult> validate) => Validators.Add(validate);
 
         /// <summary>
         /// Gets the default value for the argument.

src/System.CommandLine/ArgumentExtensions.cs

@@ -35,7 +35,7 @@ public static TArgument AddCompletions<TArgument>(
         /// </summary>
         /// <typeparam name="TArgument">The type of the argument.</typeparam>
         /// <param name="argument">The argument for which to add completions.</param>
-        /// <param name="complete">A <see cref="CompletionDelegate"/> that will be called to provide completions.</param>
+        /// <param name="complete">A function that will be called to provide completions.</param>
         /// <returns>The option being extended.</returns>
         public static TArgument AddCompletions<TArgument>(
             this TArgument argument,
@@ -52,11 +52,11 @@ public static TArgument AddCompletions<TArgument>(
         /// </summary>
         /// <typeparam name="TArgument">The type of the argument.</typeparam>
         /// <param name="argument">The argument for which to add completions.</param>
-        /// <param name="complete">A <see cref="CompletionDelegate"/> that will be called to provide completions.</param>
+        /// <param name="complete">A function that will be called to provide completions.</param>
         /// <returns>The configured argument.</returns>
         public static TArgument AddCompletions<TArgument>(
             this TArgument argument,
-            CompletionDelegate complete)
+            Func<CompletionContext, IEnumerable<CompletionItem>> complete)
             where TArgument : Argument
         {
             argument.Completions.Add(complete);

src/System.CommandLine/Argument{T}.cs

@@ -70,7 +70,7 @@ public Argument(Func<T> getDefaultValue) : this()
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="parse"/> is null.</exception>
         public Argument(
             string? name,
-            ParseArgument<T> parse, 
+            Func<ArgumentResult, T> parse, 
             bool isDefault = false,
             string? description = null) : this(name, description)
         {
@@ -108,7 +108,7 @@ public Argument(
         /// </summary>
         /// <param name="parse">A custom argument parser.</param>
         /// <param name="isDefault"><see langword="true"/> to use the <paramref name="parse"/> result as default value.</param>
-        public Argument(ParseArgument<T> parse, bool isDefault = false) : this(null!, parse, isDefault)
+        public Argument(Func<ArgumentResult, T> parse, bool isDefault = false) : this(null!, parse, isDefault)
         {
         }
 

src/System.CommandLine/Builder/CommandLineBuilderExtensions.cs

@@ -251,7 +251,7 @@ public static CommandLineBuilder UseEnvironmentVariableDirective(
         {
             builder.AddMiddleware((context, next) =>
             {
-                if (context.ParseResult.Directives.TryGetValues("env", out var keyValuePairs))
+                if (context.ParseResult.Directives.TryGetValue("env", out var keyValuePairs))
                 {
                     for (var i = 0; i < keyValuePairs.Count; i++)
                     {
@@ -498,7 +498,7 @@ public static CommandLineBuilder UseParseDirective(
         {
             builder.AddMiddleware(async (context, next) =>
             {
-                if (context.ParseResult.Directives.Contains("parse"))
+                if (context.ParseResult.Directives.ContainsKey("parse"))
                 {
                     context.InvocationResult = new ParseDirectiveResult(errorExitCode);
                 }
@@ -547,7 +547,7 @@ public static CommandLineBuilder UseSuggestDirective(
         {
             builder.AddMiddleware(async (context, next) =>
             {
-                if (context.ParseResult.Directives.TryGetValues("suggest", out var values))
+                if (context.ParseResult.Directives.TryGetValue("suggest", out var values))
                 {
                     int position;
 

src/System.CommandLine/Command.cs

@@ -22,7 +22,7 @@ public class Command : IdentifierSymbol, IEnumerable<Symbol>
         private List<Argument>? _arguments;
         private List<Option>? _options;
         private List<Command>? _subcommands;
-        private List<ValidateSymbolResult<CommandResult>>? _validators;
+        private List<Action<CommandResult>>? _validators;
 
         /// <summary>
         /// Initializes a new instance of the Command class.
@@ -68,8 +68,8 @@ public IEnumerable<Symbol> Children
         /// </summary>
         public IReadOnlyList<Command> Subcommands => _subcommands is not null ? _subcommands : Array.Empty<Command>();
 
-        internal IReadOnlyList<ValidateSymbolResult<CommandResult>> Validators
-            => _validators is not null ? _validators : Array.Empty<ValidateSymbolResult<CommandResult>>();
+        internal IReadOnlyList<Action<CommandResult>> Validators
+            => _validators is not null ? _validators : Array.Empty<Action<CommandResult>>();
 
         internal bool HasValidators => _validators is not null; // initialized by Add method, so when it's not null the Count is always > 0
 
@@ -140,8 +140,8 @@ public void AddGlobalOption(Option option)
         /// Adds a custom validator to the command. Validators can be used
         /// to create custom validation logic.
         /// </summary>
-        /// <param name="validate">The delegate to validate the symbols during parsing.</param>
-        public void AddValidator(ValidateSymbolResult<CommandResult> validate) => (_validators ??= new()).Add(validate);
+        /// <param name="validate">The action to validate the symbols during parsing.</param>
+        public void AddValidator(Action<CommandResult> validate) => (_validators ??= new()).Add(validate);
 
         /// <summary>
         /// Gets or sets a value that indicates whether unmatched tokens should be treated as errors. For example,

src/System.CommandLine/CompletionSourceExtensions.cs

@@ -18,7 +18,7 @@ public static class CompletionSourceExtensions
         /// <param name="completionSources">The list of completion sources to add to.</param>
         /// <param name="complete">The delegate to be called when calculating completions.</param>
         public static void Add(
-            this CompletionSourceList completionSources,
+            this ICollection<ICompletionSource> completionSources,
             Func<CompletionContext, IEnumerable<string>> complete)
         {
             if (completionSources is null)
@@ -38,10 +38,10 @@ public static void Add(
         /// Adds a completion source using a delegate.
         /// </summary>
         /// <param name="completionSources">The list of completion sources to add to.</param>
-        /// <param name="complete">The delegate to be called when calculating completions.</param>
+        /// <param name="complete">The function to be called when calculating completions.</param>
         public static void Add(
-            this CompletionSourceList completionSources,
-            CompletionDelegate complete)
+            this ICollection<ICompletionSource> completionSources,
+            Func<CompletionContext, IEnumerable<CompletionItem>> complete)
         {
             if (completionSources is null)
             {
@@ -62,7 +62,7 @@ public static void Add(
         /// <param name="completionSources">The list of completion sources to add to.</param>
         /// <param name="completions">A list of strings to be suggested for command line completions.</param>
         public static void Add(
-            this CompletionSourceList completionSources,
+            this ICollection<ICompletionSource> completionSources,
             params string[] completions)
         {
             if (completionSources is null)

src/System.CommandLine/Completions/AnonymousCompletionSource.cs

@@ -8,9 +8,9 @@ namespace System.CommandLine.Completions
 {
     internal class AnonymousCompletionSource : ICompletionSource
     {
-        private readonly CompletionDelegate _complete;
+        private readonly Func<CompletionContext, IEnumerable<CompletionItem>> _complete;
 
-        public AnonymousCompletionSource(CompletionDelegate complete)
+        public AnonymousCompletionSource(Func<CompletionContext, IEnumerable<CompletionItem>> complete)
         {
             _complete = complete ?? throw new ArgumentNullException(nameof(complete));
         }