RenderJS - retrieve method from subgadget on "main" gadget

gistfile1.txt

/*jslint indent: 2, maxlen: 80, nomen: true */
/*global console, window, document, rJS, RSVP, $ */
(function (window, document, rJS) {
  "use strict";

  var TRANSLATION_GADGET = "./html/translations.html";

  // prevent JQM autoinit
  $(document)
    .on("mobileinit", function () {
      $.mobile.autoInitializePage = false;
    });

  rJS(window)
    .ready(function (g) {
      g.render();
    })
    .declareMethod('render', function () {
      var gadget = this;

      return RSVP.all([
        gadget.declareGadget(TRANSLATION_GADGET, {
          element: gadget.__element,
          scope: "i18n"
        })
      ])
        .then(function (gadget_list) {
          var i, len, response_gadget, gadget_array = [];

          for (i = 0, len = gadget_list.length; i < len; i += 1) {
            response_gadget = gadget_list[i];
            if (response_gadget.render) {
              gadget_array[i] = response_gadget.render();
            }
          }

          return RSVP.all(gadget_array);
        })
        .then(function (response_list) {

          // JQM handler
          $(document)
            .on('pagebeforechange', function (e, data) {
              var target, clean_url, parsed_url, is_enhanced;

              if (e && data) {
                if (typeof data.toPage === "string") {
                  target = data.toPage.split("#")[1];

                // enable deeplinks
                } else if ($.mobile.navigate.history.initialDst &&
                      window.location.hash !== "") {

                  clean_url = window.location.href.split("#")[0];
                  parsed_url = $.mobile.path.parseUrl(clean_url);
                  target = $.mobile.navigate.history.initialDst;
                  delete $.mobile.navigate.history.initialDst;

                  $.mobile.navigate.history.stack[0].hash = "";
                  $.mobile.navigate.history.stack[0].url = clean_url;
                  $.mobile.path.documentUrl = parsed_url;
                  $.mobile.path.documentBase = parsed_url;
                }
              }

              // load new page (= gadget) when missing
              if (target && !document.getElementById(target)) {
                
                // QUESTION 1: WHY IS GADGET DEFINED HERE? WHAT ELSE SHOULD I USE? rJS(window) does not work
                return gadget.declareGadget(
                  "./html/" + target + ".html",
                  {"element": gadget.__element, "scope": target}
                )
                .then(function (new_gadget) {
                  if (new_gadget.render) {
                    new_gadget.render();
                  }
                  $.mobile.changePage("#" + target);
                  document.getElementById(target)
                    .setAttribute("data-external-page", true);
                })
                .fail(console.log);
              }
            })
            .on('pagehide', 'div.ui-page', function () {
              var page, id, is_enhanced;

              page = this;
              id = this.id;
              is_enhanced = $(page).data("mobilePage");

              if (page.getAttribute('data-external-page')) {
                if (is_enhanced) {
                  $(this).page('destroy').remove();
                }
                return gadget.dropGadget(id).fail(gadget.errorHandler);
              }
            });

          // start JQM
          $.mobile.initializePage();
          $("[data-role='footer']").toolbar();

          // QUESTION 2: WHY CAN I NOT ACQUIRE ANYTHING HERE?
          // console.log(gadget)
          // console.log(gadget.__acquired_method_dict)
          // console.log(gadget.__acquired_method_dict.acquire_changeLanguage)
          // all are defined, but the line below:
          return gadget.acquire_changeLanguage();
          // says "AcquisitionError: No gadget provides acquire_changeLanguage"
        })
        .then(function (r) {
           console.log("I NEVER TRIGGER");
        })
        .fail(console.log);
    })

    .declareAcquiredMethod("acquire_changeLanguage", "acquire_changeLanguage")

    
    .allowPublicAcquisition("acquire_changeLanguage", function (param_list) {
      return this.getDeclaredGadget("i18n")
        .then(function (i18n) {
          return i18n.changeLanguage.apply(i18n, param_list);
        });
    });

}(window, document, rJS));