Trimming spaces and Maybe

[maxigit]

I have a little problem trying to parse a csv which has spaces for null value (ex "item, ,").
The way to handle null values is obviously to use Nothing but the parser fails because the parsed string is not null but can't be parsed has an Int.

I've added some specs for what I think is the sensible behavior

, testGroup "Space trimming and Maybe"
  [ testCase "null::Int"           (expect (parseField ""     :: Parser (Maybe Int))    Nothing)
  , testCase "_::Int"              (expect (parseField " "    :: Parser (Maybe Int))    Nothing)
  , testCase "_Int"                (expect (parseField " 12"  :: Parser (Maybe Int))    (Just 12))
  , testCase "____"                (expect (parseField "    " :: Parser (Maybe Int))    Nothing)
  , testCase "null::String"        (expect (parseField ""     :: Parser (Maybe String)) Nothing)
  , testCase "quoted null::String" (expect (parseField "\"\""     :: Parser (Maybe String)) (Just ""))
  , testCase "_::String"           (expect (parseField " "    :: Parser (Maybe String)) (Just " "))

Case "null::String" and "quoted null::String" and hard to get working together.
I see many possibilities to solve the problem

1 - strip spaces before testing if a field is null in the Maybe code
2 - strip spaces at the parsing level, and maybe add a strip space options in the decodeOptions
3 - change parser to deal with Maybe by default

What do you think ? (I'm happy to help if needed).