haskell - Parse JSON with fieldnames that contain reserved keywords -

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i'm trying parse following json aeson.

{     "data": [         {             "id": "34",             "type": "link",             "story": "foo"         },         {             "id": "35",             "type": "link",             "story": "bar"         }     ] }

since there lot of field i'd ignore, seems i should use ghc generics. how write data type definition uses haskell keywords data , type? following of course gives: parse error on input `data'

data feed = feed {data :: [post]}     deriving (show, generic)  data post = post {         id :: string,         type :: string,         story :: string     }     deriving (show, generic)

you can write own fromjson , tojson instances without relying on ghc.generics. means can use different field names data representation , json representation.

example instances post:

{-# language overloadedstrings #-} import control.applicative import data.aeson import qualified data.bytestring.lazy lbs  data post = post {         postid :: string,         typ :: string,         story :: string   }   deriving (show)  instance fromjson post   parsejson (object x) = post <$> x .: "id" <*> x.: "type" <*> x .: "story"   parsejson _ = fail "expected object"  instance tojson post   tojson post = object      [ "id" .= postid post     , "type" .= typ post     , "story" .= story post     ]  main :: io () main =   print $ (decode $ post "{\"type\": \"mytype\", \"story\": \"really interresting story\", \"id\" : \"someid\"}" :: maybe post)   lbs.putstrln $ encode $ post "myid" "mytype" "some other story"

the same can done feed. if didn't have ignore fields, use derivejson data.aeson.th, takes function modify field names it's first argument.


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