Added the continueParsing option to ArgParser.

pkg/args/lib/args.dart

Index: pkg/args/lib/args.dart
diff --git a/pkg/args/lib/args.dart b/pkg/args/lib/args.dart
index 9e6252a5a2b681ffba321741056ddd25183cc852..668577cc77ced8f16d5ff23e9a3f779fbb288944 100644
--- a/pkg/args/lib/args.dart
+++ b/pkg/args/lib/args.dart
@@ -347,9 +347,20 @@ class ArgParser {
   /**
    * Parses [args], a list of command-line arguments, matches them against the
    * flags and options defined by this parser, and returns the result.
+   *
+   * If [allowTrailingOptions] is set, the parser will continue parsing even
+   * after it finds an argument that is neither an option nor a command.
+   * This allows options to be specified after regular arguments.
+   *
+   * [allowTrailingOptions] is false by default, so when a non-option,
+   * non-command argument is encountered, it and all remaining arguments,
+   * even those that look like options are passed to the innermost command.
    */
-  ArgResults parse(List<String> args) =>
-      new Parser(null, this, args.toList()).parse();
+  ArgResults parse(List<String> args, {bool allowTrailingOptions}) {
+    if (allowTrailingOptions == null) allowTrailingOptions = false;
+    return new Parser(null, this, args.toList(), null, null,
+        allowTrailingOptions: allowTrailingOptions).parse();
+  }
 
   /**
    * Generates a string displaying usage information for the defined options.