Added the ability to get the names of the options in a set of parsed arguments, and the default val…

lib/args/args.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This library lets you define parsers for parsing raw command-line arguments
  * into a set of options and values using [GNU][] and [POSIX][] style options.
  *
  * ## Defining options ##
  *
@@ skipping 471 matching lines @@
    * Finds the option whose abbreviation is [abbr], or `null` if no option has
    * that abbreviation.
    */
   _Option _findByAbbr(String abbr) {
     for (var option in _options.getValues()) {
       if (option.abbreviation == abbr) return option;
     }
 
     return null;
   }
+
+  /**
+   * Get the default value for an option. Useful after parsing to test
+   * if the user specified something other than the default.
+   */
+  getDefault(String option) {
+    if (!_options.containsKey(option)) {
+      throw new IllegalArgumentException('No option named $option');
+    }
+    return _options[option].defaultValue;
+  }
 }
 
 /**
  * The results of parsing a series of command line arguments using
  * [ArgParser.parse()]. Includes the parsed options and any remaining unparsed
  * command line arguments.
  */
 class ArgResults {
   final Map _options;
 
   /**
    * The remaining command-line arguments that were not parsed as options or
    * flags. If `--` was used to separate the options from the remaining
    * arguments, it will not be included in this list.
    */
   final List<String> rest;
 
   /** Creates a new [ArgResults]. */
   ArgResults(this._options, this.rest);
 
   /** Gets the parsed command-line option named [name]. */
   operator [](String name) {
     if (!_options.containsKey(name)) {
       throw new IllegalArgumentException(
           'Could not find an option named "$name".');
     }
 
     return _options[name];
   }
+
+  /** Get the names of the options as a [Collection]. */
+  Collection<String> get options => _options.getKeys();
 }
 
 class _Option {
   final String name;
   final String abbreviation;
   final List allowed;
   final defaultValue;
   final Function callback;
   final String help;
   final Map<String, String> allowedHelp;
@@ skipping 218 matching lines @@
       allowedBuffer.add(allowed);
       if (allowed == option.defaultValue) {
         allowedBuffer.add(' (default)');
       }
       first = false;
     }
     allowedBuffer.add(']');
     return allowedBuffer.toString();
   }
 }