Liquid

gistfile1.txt

class Liquify
  attr_accessor :content, :template

  class ::InvalidInputException < Exception; end;

  def initialize(content)
    @content = content
  end

  def template
    @template ||= Liquid::Template.parse @content
  end

  def variables
    template.root.nodelist.select{|node| node.respond_to? :name}.map{|n| n.name}
  end

  def substitute(params = {})
    unless params.class == Hash || params.class == HashWithIndifferentAccess
      raise InvalidInputException
    end

    template.render hashify params
  end

  def variables_in?(params = [])
    unless params.class == Array
      raise InvalidInputException
    end

    variables & params.map{|m| m.to_s} == variables
  end

  def variables_not_in?(params = [])
    !variables_in? params
  end

  private

  def hashify(params = {})
    hash = {}
    params.each do |k,v|
      hash[k.to_s] = v
    end

    hash
  end

end