Different ways of extending liquid

Gemfile

source "https://rubygems.org"

gem 'liquid'
gem 'RedCloth'

liquid_extensions.rb

require 'liquid'
require 'RedCloth'

# SIMPLE

@template = Liquid::Template.parse("hi {{name}}")  # Parses and compiles the template
puts @template.render( 'name' => 'tobi' )


# REGISTER FILTER

module TextFilter
  def textilize(input)
    RedCloth.new(input).to_html
  end
end

Liquid::Template.register_filter(TextFilter)

@template = Liquid::Template.parse(" {{ '*hi*' | textilize }} ")

puts @template.render              # => "<b>hi</b>"

# CUSTOM TAG

class Randomnum < Liquid::Tag
  def initialize(tag_name, max, tokens)
     super
     @max = max.to_i
  end

  def render(context)
    rand(@max).to_s
  end
end

Liquid::Template.register_tag('random', Randomnum)

@template = Liquid::Template.parse(" {% random 5 %}")

puts @template.render    # => "3"


# CUSTOM BLOCK

class Randomblock < Liquid::Block
  def initialize(tag_name, markup, tokens)
     super
     @rand = markup.to_i
  end

  def render(context)
    if rand(@rand) == 0
       super
    else
       'nope'
    end
  end
end

Liquid::Template.register_tag('randomblock', Randomblock)
text = " {% randomblock 2 %} wanna hear a joke? {% endrandomblock %} "
@template = Liquid::Template.parse(text)
puts @template.render  # => In 20% of the cases, this will output "wanna hear a joke?"