我听说 DHH 和其他 37Signal 的大佬谈了很多关于俄罗斯娃娃缓存的话题，我理解它的概念，但我真的不知道如何将它应用到我的代码中。
你会如何应用它？
新编辑：您如何将 gem 应用于包含大量 if 语句的代码？
<% if signed_in? %>
<div class="timeline">
<%= link_to image_tag(current_user.avatar), designer_path(current_user), :class => "avatar topimg" %>
<%= content_tag(:span, "your profile", :class => "description") %>
<%= link_to "", new_design_path, :class => "upload icon-upload" %>
<%= content_tag(:span, "upload a new design", :class => "description") %>
<%= link_to "", designer_path(current_user)+"/favorites", :class => "upload icon-star" unless current_user.followees_by_type("design").blank? %>
<%= content_tag(:span, "designs you've favorited", :class => "description") unless current_user.followees_by_type("design").blank? %>
<%= content_tag(:span, current_user.current_invites, :class => "invites_count") unless current_user.current_invites <= 0 || current_user.full_member == false %>
<%= link_to "", "#", :class => "invite icon-plus "+("blue" unless current_user.current_invites == 0).to_s unless current_user.current_invites < 0 || current_user.full_member == false %>
<%= content_tag(:span, "invite a friend ("+current_user.current_invites.to_s+" invites left)", :class => "description") unless current_user.current_invites < 0 %>
<%= content_tag(:span, activity, :class => "activity_count") unless activity == 0 %>
<%= link_to "", designer_path(current_user)+"/statistics", :class => "upload icon-activity "+("blue" unless activity == 0).to_s unless activity == 0 %>
<%= content_tag(:span, ("your activity ("+pluralize(activity, 'new thing')+")"), :class => "description") unless activity == 0%>
</div>
<% else %>
<%= link_to raw('<i class="icon-twitter icon-font"></i><span>login with twitter</span>'), "/auth/twitter", :class => "btn btn-twitter grey-tweet" %>
<% end %>