# File lib/sass/tree/for_node.rb, line 37
    def _perform(environment)
      from = @from.perform(environment)
      to = @to.perform(environment)
      from.assert_int!
      to.assert_int!

      to = to.coerce(from.numerator_units, from.denominator_units)
      range = Range.new(from.to_i, to.to_i, @exclusive)

      children = []
      environment = Sass::Environment.new(environment)
      range.each do |i|
        environment.set_local_var(@var, Sass::Script::Number.new(i, from.numerator_units, from.denominator_units))
        children += perform_children(environment)
      end
      children
    end