class UserAgent::Version

def initialize(str)
  @str = str
  if @str =~ /^\s*$/
    @nil        = true
    @sequences  = []
    @comparable = false
  elsif str =~ /^\d+$/ || str =~ /^\d+\./
    @nil        = false
    @sequences  = str.scan(/\d+|[A-Za-z][0-9A-Za-z-]*$/).map { |s| s =~ /^\d+$/ ? s.to_i : s }
    @comparable = true
  else
    @nil        = false
    @sequences  = [str]
    @comparable = false
  end
end