[ CLI ] Add new cli template to dart create

This new template will create a simple project with basic command line
argument processing using `package:args`.

Fixes #53126

Change-Id: I70f370bc348bb85547e4fcf2131c007416a48262
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/321800
Reviewed-by: Michael Thomsen <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>

Author: bkonyi

pkg/dartdev/lib/src/templates.dart

@@ -8,6 +8,7 @@ import 'package:collection/collection.dart' show IterableExtension;
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
 
+import 'templates/cli.dart';
 import 'templates/console.dart';
 import 'templates/console_simple.dart';
 import 'templates/package.dart';
@@ -18,6 +19,7 @@ final _substituteRegExp = RegExp(r'__([a-zA-Z]+)__');
 final _nonValidSubstituteRegExp = RegExp(r'[^a-zA-Z]');
 
 final List<Generator> generators = [
+  CliGenerator(),
   ConsoleGenerator(),
   PackageGenerator(),
   ServerShelfGenerator(),

pkg/dartdev/lib/src/templates/cli.dart

@@ -0,0 +1,120 @@
+// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import '../templates.dart';
+import 'common.dart' as common;
+
+/// A generator for a simple command-line application with argument parsing.
+class CliGenerator extends DefaultGenerator {
+  CliGenerator()
+      : super(
+          'cli',
+          'CLI Application',
+          'A command-line application with basic argument parsing.',
+          alternateId: 'console-cli',
+          categories: const ['dart', 'cli'],
+        ) {
+    addFile('.gitignore', common.gitignore);
+    addFile('analysis_options.yaml', common.analysisOptions);
+    addFile('CHANGELOG.md', common.changelog);
+    addFile('pubspec.yaml', _pubspec);
+    addFile('README.md', _readme);
+    setEntrypoint(
+      addFile('bin/__projectName__.dart', _mainDart),
+    );
+  }
+
+  @override
+  String getInstallInstructions(
+    String directory, {
+    String? scriptPath,
+  }) =>
+      super.getInstallInstructions(directory, scriptPath: 'bin/$scriptPath');
+}
+
+final String _pubspec = '''
+name: __projectName__
+description: A sample command-line application with basic argument parsing.
+version: 0.0.1
+# repository: https://github.com/my_org/my_repo
+
+environment:
+  ${common.sdkConstraint}
+
+# Add regular dependencies here.
+dependencies:
+  args: ^2.4.2
+
+dev_dependencies:
+  lints: ^2.1.0
+  test: ^1.24.0
+''';
+
+final String _readme = '''
+A sample command-line application providing basic argument parsing with an entrypoint in `bin/`.
+''';
+
+final String _mainDart = r'''
+import 'package:args/args.dart';
+
+const String version = '0.0.1';
+
+ArgParser buildParser() {
+  return ArgParser()
+    ..addFlag(
+      'help',
+      abbr: 'h',
+      negatable: false,
+      help: 'Print this usage information.',
+    )
+    ..addFlag(
+      'verbose',
+      abbr: 'v',
+      negatable: false,
+      help: 'Show additional command output.',
+    )
+    ..addFlag(
+      'version',
+      negatable: false,
+      help: 'Print the tool version.',
+    );
+}
+
+void printUsage(ArgParser argParser) {
+  print('Usage: dart __projectName__.dart <flags> [arguments]');
+  print(argParser.usage);
+}
+
+void main(List<String> arguments) {
+  final ArgParser argParser = buildParser();
+  try {
+    final ArgResults results = argParser.parse(arguments);
+    bool verbose = false;
+
+    // Process the parsed arguments.
+    if (results.wasParsed('help')) {
+      printUsage(argParser);
+      return;
+    }
+    if (results.wasParsed('version')) {
+      print('__projectName__ version: $version');
+      return;
+    }
+    if (results.wasParsed('verbose')) {
+      verbose = true;
+    }
+
+    // Act on the arguments provided.
+    print('Positional arguments: ${results.rest}');
+    if (verbose) {
+      print('[VERBOSE] All arguments: ${results.arguments}');
+    }
+  } on FormatException catch (e) {
+    // Print usage information if an invalid argument was provided.
+    print(e.message);
+    print('');
+    printUsage(argParser);
+  }
+}
+''';

pkg/dartdev/test/commands/create_test.dart

@@ -193,6 +193,10 @@ void defineCreateTests() {
         expect(lines.length, 2);
         expect(lines[0], 'cd $dir');
         expect(lines[1], 'dart run bin/server.dart');
+      } else if (generator.categories.contains('cli')) {
+        expect(lines.length, 2);
+        expect(lines[0], 'cd $dir');
+        expect(lines[1], 'dart run bin/$projectName.dart');
       } else {
         expect(lines.length, 2);
         expect(lines[0], 'cd $dir');