A helper that adds variables from the options hash to the `@` namespace (like `@root`).

create-frame-helper.js

Handlebars.registerHelper('foo', function (name, context, options) {
  var fn = Handlebars.compile(Handlebars.partials[name]);

  var frame = Handlebars.createFrame(context.data);
  for (var prop in options.hash) {
    frame[prop] = options.hash[prop];
  }

  var template = fn(context, {data: frame});
  return new Handlebars.SafeString(template);
});