This module aims to make mapping between algebraic data types and bson documents easy.

The rules: the data type must have one constructor, and named fields. All the fields must be instances of Val.

You can also generate documents with selectFields, which takes a list of functions names that of type a -> b and returns a function of type a -> Document.

Example:

 

 import Data.Bson.Mapping
 import Data.Time.Clock

 data Post = Post { time :: UTCTime
                  , author :: String
                  , content :: String 
                  , votes :: Int
                  }
           deriving (Show, Read, Eq, Ord)
 $(deriveBson ''Post)

 main :: IO ()
 main = do
   now <- getCurrentTime
   let post = Post now "francesco" "lorem ipsum" 5
   (fromBson (toBson post) :: IO Post) >>= print
   print $ toBson post
   print $ $(selectFields ['time, 'content]) post