module Text.JSON.QQ (
jsonQQ
) where
import Language.Haskell.TH
import Language.Haskell.TH.Quote
import Data.Data
import Data.Maybe
import Text.JSON
import Text.JSON.Generic
import Data.JSON.QQ
import Data.Ratio
import Text.ParserCombinators.Parsec
import Text.ParserCombinators.Parsec.Error
import Language.Haskell.Meta.Parse
jsonQQ :: QuasiQuoter
jsonQQ = QuasiQuoter {
quoteExp = jsonExp,
quotePat = \s -> error "No quotePat defined for jsonQQ",
quoteType = \s -> error "No quoteType defined for jsonQQ",
quoteDec = \s -> error "No quoteDec defined for jsonQQ"
}
jsonExp :: String -> ExpQ
jsonExp txt =
case parsed' of
Left err -> error $ "Error in jsonExp: " ++ show err
Right val -> return $toExp val
where
parsed' = parsedJson txt
toExp :: JsonValue -> Exp
toExp (JsonString str) =
AppE (ConE $ mkName "Text.JSON.JSString") (AppE (VarE $ mkName "Text.JSON.toJSString") (LitE (StringL $ str)))
toExp (JsonNull) = ConE $ mkName "Text.JSON.Types.JSNull"
toExp (JsonObject objs) =
AppE (ConE $ mkName "Text.JSON.JSObject") (AppE (VarE $ mkName "Text.JSON.toJSObject") (ListE $ jsList ))
where
jsList :: [Exp]
jsList = map objs2list (objs)
objs2list :: (HashKey,JsonValue) -> Exp
objs2list (HashStringKey k,v) = TupE [LitE (StringL k), toExp v]
objs2list (HashVarKey k,v) = TupE [VarE $ mkName k, toExp v]
toExp (JsonArray arr) =
AppE (ConE $ mkName "Text.JSON.JSArray") (ListE $ map toExp arr)
toExp (JsonNumber b rat) =
AppE (AppE (ConE $ mkName "Text.JSON.JSRational") (ConE $ mkName (if b then "True" else "False"))) (InfixE (Just (LitE (IntegerL $ numerator rat))) (VarE $ mkName "Data.Ratio.%") (Just (LitE (IntegerL $ denominator rat))))
toExp (JsonIdVar v) =
VarE $ mkName v
toExp (JsonBool b) =
AppE (ConE $ mkName "Text.JSON.JSBool") (ConE $ mkName (if b then "True" else "False"))
toExp (JsonCode exp) =
AppE (VarE $ mkName "Text.JSON.Generic.toJSON") exp