Cryptsy/API/Public/MarketData.hs

   1 {-# LANGUAGE UndecidableInstances #-}
   2 module Cryptsy.API.Public.MarketData where
   3
   4 -- aeson
   5 import Data.Aeson (FromJSON(..), Value, withObject )
   6 import Data.Aeson.Types (Parser)
   7
   8 -- base
   9 import Data.Function (($))
  10 import Data.Functor (fmap, (<$>))
  11 import Data.Traversable (mapM)
  12 import Prelude (Show(show))
  13
  14 -- text
  15 import Data.Text (Text)
  16
  17 -- unordered-containers
  18 import Data.HashMap.Strict (HashMap)
  19
  20 -- this package
  21 import Cryptsy.API.Public.Market
  22 import Cryptsy.API.Public.Num
  23 import Cryptsy.API.Public.Time
  24
  25 -- |general market data parameterized by types for prices, quantities,
  26 -- date/time values, and totals (price * quantity)
  27 newtype GMarketData p q dt t =
  28         MarketData { markets :: HashMap Text (GMarket p q dt t) }
  29         deriving Show
  30
  31 -- |default market data
  32 type MarketData = GMarketData CryptsyNum CryptsyNum CryptsyTime CryptsyNum
  33
  34 instance FromJSON (GMarket p q dt t) => FromJSON (GMarketData p q dt t) where
  35         parseJSON = parseMarketData parseJSON
  36
  37 -- |Build parser for multiple markets from parser for single market.
  38 parseMarketData :: (Value -> Parser (GMarket p q dt t)) -- ^ market parser
  39                 -> Value -> Parser (GMarketData p q dt t)
  40 parseMarketData parseSingle =
  41         withObject "MarketData" $ fmap MarketData <$> mapM parseSingle