Parsing with Ocamllex and Menhir: Minor errors in `output_value`

[AmateurECE]

Thanks for the great reference to OCaml! I've been using the book to learn the language. I think there's a bug in the (non-printed) definition of print_list here. The definition is:

and print_list outc arr =
  Out_channel.output_string outc "[";
  List.iteri
    ~f:(fun i v ->
      if i > 0 then Out_channel.output_string outc ", ";
      Out_channel.output_value outc v)
    arr;
  Out_channel.output_string outc "]"

But I think this definition is meant to call the local function output_value, instead of Out_channel.output_value. When I run this with a basic JSON document, it prints some garbage characters to my terminal. I changed it to this:

and print_list outc arr =
  Out_channel.output_string outc "[";
  List.iteri
    ~f:(fun i v ->
      if i > 0 then Out_channel.output_string outc ",";
      output_value outc v)
    arr;
  Out_channel.output_string outc "]"

And this has been working for me. Additionally, I noticed that the definition of output_value does not escape double quotes, which causes some issues when piping to jq or other. So I added this function, and updated output_value to use it:

and print_string outc s =
  let escaped = CCString.replace ~sub:"\"" ~by:"\\\"" s in
  Out_channel.output_string outc ("\"" ^ escaped ^ "\"")

This may not matter since these definitions aren't rendered in the book but I thought I might mention it anyways!