Update charted to 0.4.8 and roll

packages/args/lib/src/parser.dart

Index: packages/args/lib/src/parser.dart
diff --git a/packages/args/lib/src/parser.dart b/packages/args/lib/src/parser.dart
index a10692d4ed84e328122ecefce672089a48dede34..64374fcb1a1677aa488ebe418d9668b5fc6ad947 100644
--- a/packages/args/lib/src/parser.dart
+++ b/packages/args/lib/src/parser.dart
@@ -2,9 +2,8 @@
 // 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.parser;
-
 import 'arg_parser.dart';
+import 'arg_parser_exception.dart';
 import 'arg_results.dart';
 import 'option.dart';
 
@@ -37,7 +36,8 @@ class Parser {
   /// The accumulated parsed options.
   final Map<String, dynamic> results = <String, dynamic>{};
 
-  Parser(this.commandName, this.grammar, this.args, this.parent, rest) {
+  Parser(this.commandName, this.grammar, this.args,
+      [this.parent, List<String> rest]) {
     if (rest != null) this.rest.addAll(rest);
   }
 
@@ -64,7 +64,15 @@ class Parser {
         validate(rest.isEmpty, 'Cannot specify arguments before a command.');
         var commandName = args.removeAt(0);
         var commandParser = new Parser(commandName, command, args, this, rest);
-        commandResults = commandParser.parse();
+
+        try {
+          commandResults = commandParser.parse();
+        } on ArgParserException catch (error) {
+          if (commandName == null) rethrow;
+          throw new ArgParserException(
+              error.message,
+              [commandName]..addAll(error.commands));
+        }
 
         // All remaining arguments were passed to command so clear them here.
         rest.clear();
@@ -243,9 +251,9 @@ class Parser {
 
   /// Called during parsing to validate the arguments.
   ///
-  /// Throws a [FormatException] if [condition] is `false`.
+  /// Throws an [ArgParserException] if [condition] is `false`.
   void validate(bool condition, String message) {
-    if (!condition) throw new FormatException(message);
+    if (!condition) throw new ArgParserException(message);
   }
 
   /// Validates and stores [value] as the value for [option], which must not be
@@ -259,7 +267,7 @@ class Parser {
       return;
     }
 
-    var list = results.putIfAbsent(option.name, () => []);
+    var list = results.putIfAbsent(option.name, () => <String>[]);
 
     if (option.splitCommas) {
       for (var element in value.split(",")) {