Parse comma-separated multiple values.

lib/src/arg_parser.dart

 // 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.arg_parser;
 
 import 'dart:collection';
 
 import 'arg_results.dart';
 import 'option.dart';
@@ skipping 59 matching lines @@
   void addFlag(String name, {String abbr, String help, bool defaultsTo: false,
       bool negatable: true, void callback(bool value), bool hide: false}) {
     _addOption(name, abbr, help, null, null, null, defaultsTo, callback,
         OptionType.FLAG, negatable: negatable, hide: hide);
   }
 
   /// Defines a value-taking option. Throws an [ArgumentError] if:
   ///
   /// * There is already an option with name [name].
   /// * There is already an option using abbreviation [abbr].
+  /// * [splitCommas] is passed but [allowMultiple] is `false`.
   void addOption(String name, {String abbr, String help, String valueHelp,
       List<String> allowed, Map<String, String> allowedHelp, String defaultsTo,
-      void callback(value), bool allowMultiple: false, bool hide: false}) {
+      void callback(value), bool allowMultiple: false, bool splitCommas,
+      bool hide: false}) {
+    if (!allowMultiple && splitCommas != null) {
+      throw new ArgumentError(
+          'splitCommas may not be set if allowMultiple is false.');

[Sean Eagan, 2015/03/04 22:28:03]

Why not?  Seems like it would be reasonable that someone would want to allow
e.g.
`--foo=a,b,c`, but not `--foo=a,b --foo=c`.  In fact the latter seems kind of
useless.

[nweiz, 2015/03/04 22:39:55]

Why would you want to forbid the latter? That provides no additional
expressiveness, and is contrary to how many existing command-line tools work.

+    }
+
     _addOption(name, abbr, help, valueHelp, allowed, allowedHelp, defaultsTo,
         callback, allowMultiple ? OptionType.MULTIPLE : OptionType.SINGLE,
-        hide: hide);
+        splitCommas: splitCommas, hide: hide);
   }
 
   void _addOption(String name, String abbr, String help, String valueHelp,
       List<String> allowed, Map<String, String> allowedHelp, defaultsTo,
       void callback(value), OptionType type,
-      {bool negatable: false, bool hide: false}) {
+      {bool negatable: false, bool splitCommas, bool hide: false}) {
     // Make sure the name isn't in use.
     if (_options.containsKey(name)) {
       throw new ArgumentError('Duplicate option "$name".');
     }
 
     // Make sure the abbreviation isn't too long or in use.
     if (abbr != null) {
       var existing = findByAbbreviation(abbr);
       if (existing != null) {
         throw new ArgumentError(
             'Abbreviation "$abbr" is already used by "${existing.name}".');
       }
     }
 
     _options[name] = newOption(name, abbr, help, valueHelp, allowed,
         allowedHelp, defaultsTo, callback, type,
-        negatable: negatable, hide: hide);
+        negatable: negatable, splitCommas: splitCommas, hide: hide);
   }
 
   /// Parses [args], a list of command-line arguments, matches them against the
   /// flags and options defined by this parser, and returns the result.
   ArgResults parse(List<String> args) =>
       new Parser(null, this, args.toList(), null, null).parse();
 
   /// Generates a string displaying usage information for the defined options.
   ///
   /// This is basically the help text shown on the command line.
@@ skipping 14 matching lines @@
     return options[option].defaultValue;
   }
 
   /// Finds the option whose abbreviation is [abbr], or `null` if no option has
   /// that abbreviation.
   Option findByAbbreviation(String abbr) {
     return options.values.firstWhere((option) => option.abbreviation == abbr,
         orElse: () => null);
   }
 }