[Haskell-beginners] Aeson: parsing json with 'data' field

[Derek McLoughlin]

{-# LANGUAGE OverloadedStrings #-}

import Data.Aeson ((.:), (.:?), decode, FromJSON(..), Value(..))
import Control.Applicative ((<$>), (<*>))
import qualified Data.ByteString.Lazy.Char8 as BS

data Foo = Foo {
              _data :: String -- call it anything you like
           }
           deriving (Show)

instance FromJSON Foo where
  parseJSON (Object v) =
    Foo <$>
    (v .: "data")

Testing:

ghci> let json = BS.pack "{\"data\":\"hello\"}"
ghci> let (Just x) = decode json :: Maybe Foo|
ghci> x
Foo {_data = "hello"}



On 4 October 2014 08:07, Miro Karpis <miroslav.karpis at gmail.com> wrote:
> Hi,
> please can you help me with this.......I have a json file which contains a
> field with name "data". Problem is that I can not create a data type with
> "data", (or can I)? How else can I handle this? I know I can convert all
> json to Object and then search for the field....but I was hoping for some
> friendly/easier option.
>
>
> json example:
>
> {
>   "data" : {
>     "foo" : "bar"
>   }
> }
>
>
> below definition returns: parse error on input ‘data’
> data Foo = Foo {
>   data :: String
> }
>
>
> Cheers,
> Miro
>
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