class Liquid::Cycle

{% cycle string, string, … %}
@liquid_syntax
> Use the ‘cycle` tag to output text in a predictable pattern. For example, to apply odd/even classes to rows in a table.
> Tip:
The `cycle` tag must be used inside a `for` loop.
@liquid_description
Loops through a group of strings and outputs them one at a time for each iteration of a [`for` loop](/docs/api/liquid/tags/for).
@liquid_summary
@liquid_name cycle
@liquid_category iteration
@liquid_type tag
@liquid_public_docs

def initialize(tag_name, markup, options) 

def initialize(tag_name, markup, options)
  super
  case markup
  when NamedSyntax
    @variables = variables_from_string(Regexp.last_match(2))
    @name      = parse_expression(Regexp.last_match(1))
    @is_named = true
  when SimpleSyntax
    @variables = variables_from_string(markup)
    @name      = @variables.to_s
    @is_named = !@name.match?(/\w+:0x\h{8}/)
  else
    raise SyntaxError, options[:locale].t("errors.syntax.cycle")
  end
end

def named? 

def named?
  @is_named
end

def render_to_output_buffer(context, output) 

def render_to_output_buffer(context, output)
  context.registers[:cycle] ||= {}
  key       = context.evaluate(@name)
  iteration = context.registers[:cycle][key].to_i
  val = context.evaluate(@variables[iteration])
  if val.is_a?(Array)
    val = val.join
  elsif !val.is_a?(String)
    val = val.to_s
  end
  output << val
  iteration += 1
  iteration = 0 if iteration >= @variables.size
  context.registers[:cycle][key] = iteration
  output
end

def variables_from_string(markup) 

def variables_from_string(markup)
  markup.split(',').collect do |var|
    var =~ /\s*(#{QuotedFragment})\s*/o
    Regexp.last_match(1) ? parse_expression(Regexp.last_match(1)) : nil
  end.compact
end