gistfile1.rb

def user_agent(pattern)
  condition {
    if request.user_agent =~ pattern
      @params[:agent] = $~[1..-1]
      true
    else
      false
    end
  }
end
alias_method :agent, :user_agent

def get(path, opts={}, &block)
  conditions = @conditions.dup
  route('GET', path, opts, &block)

  @conditions = conditions
  route('HEAD', path, opts, &block)
end

def route(verb, path, options={}, &block)
  # Because of self.options.host
  host_name(options.delete(:bind)) if options.key?(:host)

  options.each {|option, args| send(option, *args)}

  pattern, keys = compile(path)
  conditions, @conditions = @conditions, []
  ...