aside_block.rb

# AsideBlock
# Insert toggle-able text segments with ease in Jekyll blog posts.
# Requires Bootstrap
#
# Author: Matthew Chan <matt@themattchan.com>
# Date: January 2015
# License: GNU GPL
#
# Usage:
# {% aside <title> %} ==> auto expands to "(aside) <title>"
# <markdown body>
# {% endaside %}

module Jekyll
  class AsideBlock < Liquid::Block

    def initialize(tag_name, text, tokens)
      super
       # text = <title>, everything after the aside token in {% aside ... %}
      @text = "(aside) " + text
    end

    require "kramdown"
    def render(context)
      content = super
      content = "#{Kramdown::Document.new(content,:input => 'GFM').to_html}"

      gensym = rand_id

      %Q|<div id="aside-#{gensym}" class="panel panel-default"> <div
          class="panel-heading"> <p class="panel-title"><b> <a
          href="\#aside-#{gensym}\#aside-text-#{gensym}" data-toggle="collapse">
          #{@text} </a> </b></p> </div> <div id="aside-text-#{gensym}"
          class="panel-body collapse">#{content}</div></div>|
    end

    def rand_id
      o = [('a'..'z'), ('A'..'Z')].map { |i| i.to_a }.flatten
      string = (0...10).map { o[rand(o.length)] }.join
      string
    end

  end
end
Liquid::Template.register_tag('aside', Jekyll::AsideBlock)