change Parser constructor that accepts Symbol to accept Command

Author: jonsequitur

src/System.CommandLine.Tests/ArgumentTests.cs

@@ -500,6 +500,42 @@ public void Parse_delegate_is_called_once_per_parse_operation()
                 i.Should().Be(2);
             }
 
+            [Theory] // https://github.com/dotnet/command-line-api/issues/1294
+            [InlineData("", "option-is-implicit")]
+            [InlineData("--bananas", "argument-is-implicit")]
+            [InlineData("--bananas argument-is-specified", "argument-is-specified")]
+            public void Parse_delegate_is_called_when_Option_Arity_allows_zero_tokens(string commandLine, string expectedValue)
+            {
+                var opt = new Option<string>(
+                    "--bananas",
+                    parseArgument: result =>
+                    {
+                        if (result.Tokens.Count == 0)
+                        {
+                            if (result.Parent is OptionResult { IsImplicit: true })
+                            {
+                                return "option-is-implicit";
+                            }
+
+                            return "argument-is-implicit";
+                        }
+                        else
+                        {
+                            return result.Tokens[0].Value;
+                        }
+                    }, isDefault: true)
+                {
+                    Arity = ArgumentArity.ZeroOrOne
+                };
+
+                var rootCommand = new RootCommand
+                {
+                    opt
+                };
+
+                rootCommand.Parse(commandLine).ValueForOption(opt).Should().Be(expectedValue);
+            }
+
             [Theory]
             [InlineData("1 2 3 4 5 6 7 8")]
             [InlineData("-o 999 1 2 3 4 5 6 7 8")]

src/System.CommandLine.Tests/Binding/ModelBinderTests.cs

@@ -493,9 +493,8 @@ public void PropertyExpression_can_be_bound_to_argument()
         public void Option_argument_is_bound_to_longest_constructor()
         {
             var option = new Option<int>("--int-property");
-            var parser = new Parser(option);
 
-            var bindingContext = new BindingContext(parser.Parse("--int-property 42"));
+            var bindingContext = new BindingContext(option.Parse("--int-property 42"));
             var binder = new ModelBinder<ClassWithMultipleCtor>();
             var instance = binder.CreateInstance(bindingContext) as ClassWithMultipleCtor;
 

src/System.CommandLine.Tests/Binding/TypeConversionTests.cs

@@ -121,9 +121,8 @@ public void Argument_infers_arity_of_IEnumerable_types_as_OneOrMore(Type type)
         public void Argument_bool_will_default_to_true_when_no_argument_is_passed()
         {
             var option = new Option<bool>("-x");
-            var parser = new Parser(option);
 
-            var result = parser.Parse("-x");
+            var result = option.Parse("-x");
 
             result.Errors.Should().BeEmpty();
             result.GetValueForOption(option).Should().Be(true);

src/System.CommandLine.Tests/ParsingValidationTests.cs

@@ -25,11 +25,10 @@ public ParsingValidationTests(ITestOutputHelper output)
         [Fact]
         public void When_an_option_accepts_only_specific_arguments_but_a_wrong_one_is_supplied_then_an_informative_error_is_returned()
         {
-            var parser = new Parser(
-                new Option("-x", arity: ArgumentArity.ExactlyOne)
-                    .FromAmong("this", "that", "the-other-thing"));
-
-            var result = parser.Parse("-x none-of-those");
+            var option = new Option("-x", arity: ArgumentArity.ExactlyOne)
+                .FromAmong("this", "that", "the-other-thing");
+            
+            var result = option.Parse("-x none-of-those");
 
             result.Errors
                   .Select(e => e.Message)
@@ -44,9 +43,7 @@ public void When_an_option_has_en_error_then_the_error_has_a_reference_to_the_op
             var option = new Option("-x", arity: ArgumentArity.ExactlyOne)
                 .FromAmong("this", "that");
 
-            var parser = new Parser(option);
-
-            var result = parser.Parse("-x something_else");
+            var result = option.Parse("-x something_else");
 
             result.Errors
                   .Where(e => e.SymbolResult != null)
@@ -57,9 +54,9 @@ public void When_an_option_has_en_error_then_the_error_has_a_reference_to_the_op
         [Fact]
         public void When_a_required_argument_is_not_supplied_then_an_error_is_returned()
         {
-            var parser = new Parser(new Option("-x", arity: ArgumentArity.ExactlyOne));
+            var option = new Option("-x", arity: ArgumentArity.ExactlyOne);
 
-            var result = parser.Parse("-x");
+            var result = option.Parse("-x");
 
             result.Errors
                   .Should()
@@ -894,10 +891,9 @@ public void A_command_with_subcommands_is_valid_to_invoke_if_it_has_a_handler()
         [Fact]
         public void When_an_option_has_a_default_value_it_is_not_valid_to_specify_the_option_without_an_argument()
         {
-            var parser = new Parser(
-                new Option<int>("-x", () => 123));
+            var option = new Option<int>("-x", () => 123);
 
-            var result = parser.Parse("-x");
+            var result = option.Parse("-x");
 
             result.Errors
                   .Select(e => e.Message)

src/System.CommandLine/CommandLineConfiguration.cs

@@ -22,7 +22,7 @@ public class CommandLineConfiguration
         /// <summary>
         /// Initializes a new instance of the CommandLineConfiguration class.
         /// </summary>
-        /// <param name="symbol">The symbol to parse.</param>
+        /// <param name="command">The symbol to parse.</param>
         /// <param name="enablePosixBundling"><see langword="true"/> to enable POSIX bundling; otherwise, <see langword="false"/>.</param>
         /// <param name="enableDirectives"><see langword="true"/> to enable directive parsing; otherwise, <see langword="false"/>.</param>
         /// <param name="enableLegacyDoubleDashBehavior">Enables the legacy behavior of the <c>--</c> token, which is to ignore parsing of subsequent tokens and place them in the <see cref="ParseResult.UnparsedTokens"/> list.</param>
@@ -32,7 +32,7 @@ public class CommandLineConfiguration
         /// <param name="helpBuilderFactory">Provide a custom help builder.</param>
         /// <param name="configureHelp">Configures the help builder.</param>
         public CommandLineConfiguration(
-            Symbol symbol,
+            Command command,
             bool enablePosixBundling = true,
             bool enableDirectives = true,
             bool enableLegacyDoubleDashBehavior = false,
@@ -42,27 +42,11 @@ public CommandLineConfiguration(
             Func<BindingContext, IHelpBuilder>? helpBuilderFactory = null,
             Action<IHelpBuilder>? configureHelp = null)
         {
-            if (symbol is null)
-            {
-                throw new ArgumentNullException(nameof(symbol));
-            }
-
-            if (symbol is Command rootCommand)
-            {
-                RootCommand = rootCommand;
-            }
-            else
-            {
-                rootCommand = new RootCommand();
-
-                rootCommand.Add(symbol);
-
-                RootCommand = rootCommand;
-            }
+            RootCommand = command ?? throw new ArgumentNullException(nameof(command));
 
             _symbols.Add(RootCommand);
 
-            AddGlobalOptionsToChildren(rootCommand);
+            AddGlobalOptionsToChildren(command);
 
             EnableLegacyDoubleDashBehavior = enableLegacyDoubleDashBehavior;
             EnablePosixBundling = enablePosixBundling;

src/System.CommandLine/Parsing/Parser.cs

@@ -22,7 +22,8 @@ public Parser(CommandLineConfiguration configuration)
             }
         }
 
-        public Parser(Symbol symbol) : this(new CommandLineConfiguration(symbol))
+        /// <param name="command">The root command for the parser.</param>
+        public Parser(Command command) : this(new CommandLineConfiguration(command))
         {
         }