Usage with csv files that contain escaped double quote entries

[neenjaw]

Hello, I am a little unclear from the documentation how to use this library with a CSV file that contains an entry with already escaped double quote:

testfile:

1,"Hello \"World\""

test.exs:

NimbleCSV.define(MyParser, separator: ",", escape: ~S'"')

stdio = IO.stream(:stdio, :line)

stdio
|> Stream.map(&String.trim/1)
|> MyParser.parse_stream()
|> Enum.to_list()

I would expect this to succeed with [[1, "Hello \"World\""]], but I encounter this error:

➜ cat testfile | mix run test.exs
** (NimbleCSV.ParseError) unexpected escape character " in "Hello \\\"World\\\"\""
    deps/nimble_csv/lib/nimble_csv.ex:485: MyParser.escape/6
    deps/nimble_csv/lib/nimble_csv.ex:355: anonymous fn/4 in MyParser.parse_stream/2
    (elixir 1.10.4) lib/stream.ex:902: Stream.do_transform_user/6
    (elixir 1.10.4) lib/enum.ex:3383: Enum.reverse/1
    (elixir 1.10.4) lib/enum.ex:2984: Enum.to_list/1

[josevalim]

In CSV, the way to escape the escape character is by having it appear twice. So the format that you have written is not really supported. It will work if you rewrite it as 1,"Hello ""World""" though.

[neenjaw]

Okay, good to know! Thanks