class Liquid::Drop

def self.invokable_methods
  @invokable_methods ||= begin
    blacklist = Liquid::Drop.public_instance_methods + [:each]
    if include?(Enumerable)
      blacklist += Enumerable.public_instance_methods
      blacklist -= [:sort, :count, :first, :min, :max]
    end
    whitelist = [:to_liquid] + (public_instance_methods - blacklist)
    Set.new(whitelist.map(&:to_s))
  end
end