# File lib/mechanize/util.rb, line 89
  def self.uri_escape str, unsafe = nil
    @parser ||= begin
                  URI::Parser.new
                rescue NameError
                  URI
                end

    if URI == @parser then
      unsafe ||= URI::UNSAFE
    else
      unsafe ||= @parser.regexp[:UNSAFE]
    end

    @parser.escape str, unsafe
  end