Add a CommandRunner example (#220)
* Add a command runner example
* Update readme
* Review comments
diff --git a/example/arg_parser/README.md b/example/arg_parser/README.md
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+# Example of using `ArgParser`
+
+`dart run example.dart`
diff --git a/example/example.dart b/example/arg_parser/example.dart
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rename from example/example.dart
rename to example/arg_parser/example.dart
diff --git a/example/arg_parser/pubspec.yaml b/example/arg_parser/pubspec.yaml
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+# Copyright (c) 2022, 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.
+
+name: arg_parser_example
+version: 1.0.0
+description: An example of using ArgParser
+publish_to: 'none'
+environment:
+ sdk: '>=2.14.0 <3.0.0'
+dependencies:
+ args:
+ path: ../..
diff --git a/example/command_runner/README.md b/example/command_runner/README.md
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+# Example of using `CommandRunner`
+
+This example uses `CommandRunner` to create a tool for drawing ascii art shapes.
+
+`dart run draw.dart circle --radius=10`
diff --git a/example/command_runner/draw.dart b/example/command_runner/draw.dart
new file mode 100644
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+++ b/example/command_runner/draw.dart
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+// Copyright (c) 2022, 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 'dart:async';
+import 'dart:math';
+
+import 'package:args/command_runner.dart';
+
+void main(List<String> args) async {
+ final runner = CommandRunner<String>('draw', 'Draws shapes')
+ ..addCommand(SquareCommand())
+ ..addCommand(CircleCommand())
+ ..addCommand(TriangleCommand());
+ runner.argParser.addOption('char', help: 'The character to use for drawing');
+ final output = await runner.run(args);
+ print(output);
+}
+
+class SquareCommand extends Command<String> {
+ SquareCommand() {
+ argParser.addOption('size', help: 'Size of the square');
+ }
+
+ @override
+ String get name => 'square';
+
+ @override
+ String get description => 'Draws a square';
+
+ @override
+ List<String> get aliases => ['s'];
+
+ @override
+ FutureOr<String>? run() {
+ final size = int.parse(argResults?['size'] ?? '20');
+ final char = globalResults?['char']?[0] ?? '#';
+ return draw(size, size, char, (x, y) => true);
+ }
+}
+
+class CircleCommand extends Command<String> {
+ CircleCommand() {
+ argParser.addOption('radius', help: 'Radius of the circle');
+ }
+
+ @override
+ String get name => 'circle';
+
+ @override
+ String get description => 'Draws a circle';
+
+ @override
+ List<String> get aliases => ['c'];
+
+ @override
+ FutureOr<String>? run() {
+ final size = 2 * int.parse(argResults?['radius'] ?? '10');
+ final char = globalResults?['char']?[0] ?? '#';
+ return draw(size, size, char, (x, y) => x * x + y * y < 1);
+ }
+}
+
+class TriangleCommand extends Command<String> {
+ TriangleCommand() {
+ addSubcommand(EquilateralTriangleCommand());
+ addSubcommand(IsoscelesTriangleCommand());
+ }
+
+ @override
+ String get name => 'triangle';
+
+ @override
+ String get description => 'Draws a triangle';
+
+ @override
+ List<String> get aliases => ['t'];
+}
+
+class EquilateralTriangleCommand extends Command<String> {
+ EquilateralTriangleCommand() {
+ argParser.addOption('size', help: 'Size of the triangle');
+ }
+
+ @override
+ String get name => 'equilateral';
+
+ @override
+ String get description => 'Draws an equilateral triangle';
+
+ @override
+ List<String> get aliases => ['e'];
+
+ @override
+ FutureOr<String>? run() {
+ final size = int.parse(argResults?['size'] ?? '20');
+ final char = globalResults?['char']?[0] ?? '#';
+ return drawTriangle(size, size * sqrt(3) ~/ 2, char);
+ }
+}
+
+class IsoscelesTriangleCommand extends Command<String> {
+ IsoscelesTriangleCommand() {
+ argParser.addOption('width', help: 'Width of the triangle');
+ argParser.addOption('height', help: 'Height of the triangle');
+ }
+
+ @override
+ String get name => 'isosceles';
+
+ @override
+ String get description => 'Draws an isosceles triangle';
+
+ @override
+ List<String> get aliases => ['i'];
+
+ @override
+ FutureOr<String>? run() {
+ final width = int.parse(argResults?['width'] ?? '50');
+ final height = int.parse(argResults?['height'] ?? '10');
+ final char = globalResults?['char']?[0] ?? '#';
+ return drawTriangle(width, height, char);
+ }
+}
+
+String draw(
+ int width, int height, String char, bool Function(double, double) pixel) {
+ final out = StringBuffer();
+ for (int y = 0; y <= height; ++y) {
+ final ty = 2 * y / height - 1;
+ for (int x = 0; x <= width; ++x) {
+ final tx = 2 * x / width - 1;
+ out.write(pixel(tx, ty) ? char : ' ');
+ }
+ out.write('\n');
+ }
+ return out.toString();
+}
+
+String drawTriangle(int width, int height, String char) {
+ return draw(width, height, char, (x, y) => x.abs() <= (1 + y) / 2);
+}
diff --git a/example/command_runner/pubspec.yaml b/example/command_runner/pubspec.yaml
new file mode 100644
index 0000000..0745be6
--- /dev/null
+++ b/example/command_runner/pubspec.yaml
@@ -0,0 +1,13 @@
+# Copyright (c) 2022, 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.
+
+name: command_runner_example
+version: 1.0.0
+description: An example of using CommandRunner
+publish_to: 'none'
+environment:
+ sdk: '>=2.14.0 <3.0.0'
+dependencies:
+ args:
+ path: ../..
