Double quote to single quote, but check carefully like dstr

[sanemat]

$ cat foo.rb |ruby-parse-wrapped -
(begin
  (send nil :puts
    (str "foo"))
  (send nil :puts
    (str "bar"))
  (send nil :puts
    (dstr
      (str "too")
      (begin
        (send
          (const nil :Time) :now)))))

$ cat foo.rb
puts "foo"
puts 'bar'
puts "too#{Time.now}"