Chaining strings between babel blocks: why so many '\'?

[Alan Schmitt <alan.schmitt@polytechnique.org>]

Hello,

I've been playing with block chaining to generate some dot file then to
export then as images. I had a little trouble finding the number of '\'
I need to put in front of a quote if I want the quote to be quoted. Here
is a way to make it work:

--8<---------------cut here---------------start------------->8---
#+name: foo
#+begin_src emacs-lisp :exports none
"bar [label = \"\\\\\"test1\\\\\"\"]\nbaz [label = \"\\\\\"test2\\\\\"\"]"
#+end_src

#+results: foo
: bar [label = "\\"test1\\""]
: baz [label = "\\"test2\\""]

#+begin_src dot :file ~/tmp/test-dot.png :var input=foo :exports results
graph {
  $input
}
#+end_src
--8<---------------cut here---------------end--------------->8---

My question is: why can't I simply use this:

--8<---------------cut here---------------start------------->8---
#+name: foo
#+begin_src emacs-lisp :exports none
"bar [label = \"\\\"test1\\\"\"]\nbaz [label = \"\\\"test2\\\"\"]"
#+end_src

#+results: foo
: bar [label = "\"test1\""]
: baz [label = "\"test2\""]
--8<---------------cut here---------------end--------------->8---

(I guess the answer is in the error in replace-regexp-in-string:
(error "Invalid use of `\\' in replacement text")
.)

Would it be problematic to first transform every "\\" into a "\\\\" in
org-babel-expand-body:dot, before the call to replace-regexp-in-string?

Thanks,

Alan