Add .wasParsed() to ArgResults.

pkg/args/lib/src/option.dart

Index: pkg/args/lib/src/option.dart
diff --git a/pkg/args/lib/src/option.dart b/pkg/args/lib/src/option.dart
new file mode 100644
index 0000000000000000000000000000000000000000..6edc8abcfb493672ee7f1d0d98d6ba19ce937b4e
--- /dev/null
+++ b/pkg/args/lib/src/option.dart
@@ -0,0 +1,124 @@
+// Copyright (c) 2014, 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.
+
+library args.src.option;
+
+import 'package:collection/wrappers.dart';
+
+/// Creates a new [Option].
+///
+/// Since [Option] doesn't have a public constructor, this lets [ArgParser]
+/// get to it. This function isn't exported to the public API of the package.
+Option newOption(String name, String abbreviation, String help,
+    String valueHelp, List<String> allowed, Map<String, String> allowedHelp,
+    defaultValue, Function callback, OptionType type,
+    {bool negatable, bool hide: false}) {
+  return new Option._(name, abbreviation, help, valueHelp, allowed, allowedHelp,
+      defaultValue, callback, type, negatable: negatable, hide: hide);
+}
+
+/// A command-line option. Includes both flags and options which take a value.
+class Option {
+  final String name;
+  final String abbreviation;
+  final List<String> allowed;
+  final defaultValue;
+  final Function callback;
+  final String help;
+  final String valueHelp;
+  final Map<String, String> allowedHelp;
+  final OptionType type;
+  final bool negatable;
+  final bool hide;
+
+  /// Whether the option is boolean-valued flag.
+  bool get isFlag => type == OptionType.FLAG;
+
+  /// Whether the option takes a single value.
+  bool get isSingle => type == OptionType.SINGLE;
+
+  /// Whether the option allows multiple values.
+  bool get isMultiple => type == OptionType.MULTIPLE;
+
+  Option._(this.name, this.abbreviation, this.help, this.valueHelp,
+      List<String> allowed, Map<String, String> allowedHelp, this.defaultValue,
+      this.callback, this.type, {this.negatable, this.hide: false}) :
+        this.allowed = allowed == null ?
+            null : new UnmodifiableListView(allowed),
+        this.allowedHelp = allowedHelp == null ?
+            null : new UnmodifiableMapView(allowedHelp) {
+
+    if (name.isEmpty) {
+      throw new ArgumentError('Name cannot be empty.');
+    } else if (name.startsWith('-')) {
+      throw new ArgumentError('Name $name cannot start with "-".');
+    }
+
+    // Ensure name does not contain any invalid characters.
+    if (_invalidChars.hasMatch(name)) {
+      throw new ArgumentError('Name "$name" contains invalid characters.');
+    }
+
+    if (abbreviation != null) {
+      if (abbreviation.length != 1) {
+        throw new ArgumentError('Abbreviation must be null or have length 1.');
+      } else if(abbreviation == '-') {
+        throw new ArgumentError('Abbreviation cannot be "-".');
+      }
+
+      if (_invalidChars.hasMatch(abbreviation)) {
+        throw new ArgumentError('Abbreviation is an invalid character.');
+      }
+    }
+  }
+
+  /// Returns [value] if non-`null`, otherwise returns the default value for
+  /// this option.
+  ///
+  /// For single-valued options, it will be [defaultValue] if set or `null`
+  /// otherwise. For multiple-valued options, it will be an empty list or a
+  /// list containing [defaultValue] if set.
+  dynamic getOrDefault(value) {
+    if (value != null) return value;
+
+    if (!isMultiple) return defaultValue;
+    if (defaultValue != null) return [defaultValue];
+    return [];
+  }
+
+  static final _invalidChars = new RegExp(r'''[ \t\r\n"'\\/]''');
+}
+
+/// What kinds of values an option accepts.
+class OptionType {
+  /// An option that can only be `true` or `false`.
+  ///
+  /// The presence of the option name itself in the argument list means `true`.
+  static const FLAG = const OptionType._("OptionType.FLAG");
+
+  /// An option that takes a single value.
+  ///
+  /// Examples:
+  ///
+  ///     --mode debug
+  ///     -mdebug
+  ///     --mode=debug
+  ///
+  /// If the option is passed more than once, the last one wins.
+  static const SINGLE = const OptionType._("OptionType.SINGLE");
+
+  /// An option that allows multiple values.
+  ///
+  /// Example:
+  ///
+  ///     --output text --output xml
+  ///
+  /// In the parsed [ArgResults], a multiple-valued option will always return
+  /// a list, even if one or no values were passed.
+  static const MULTIPLE = const OptionType._("OptionType.MULTIPLE");
+
+  final String name;
+
+  const OptionType._(this.name);
+}