--- /dev/null
+/*:nodoc:*
+ * class ActionHelp
+ *
+ * Support action for printing help
+ * This class inherided from [[Action]]
+ **/
+'use strict';
+
+var util = require('util');
+
+var Action = require('../action');
+
+// Constants
+var $$ = require('../const');
+
+/*:nodoc:*
+ * new ActionHelp(options)
+ * - options (object): options hash see [[Action.new]]
+ *
+ **/
+var ActionHelp = module.exports = function ActionHelp(options) {
+ options = options || {};
+ if (options.defaultValue !== null) {
+ options.defaultValue = options.defaultValue;
+ }
+ else {
+ options.defaultValue = $$.SUPPRESS;
+ }
+ options.dest = (options.dest !== null ? options.dest: $$.SUPPRESS);
+ options.nargs = 0;
+ Action.call(this, options);
+
+};
+util.inherits(ActionHelp, Action);
+
+/*:nodoc:*
+ * ActionHelp#call(parser, namespace, values, optionString)
+ * - parser (ArgumentParser): current parser
+ * - namespace (Namespace): namespace for output data
+ * - values (Array): parsed values
+ * - optionString (Array): input option string(not parsed)
+ *
+ * Print help and exit
+ **/
+ActionHelp.prototype.call = function (parser) {
+ parser.printHelp();
+ parser.exit();
+};