module Database.Selda.SQL where
import Database.Selda.Column
import Database.Selda.SqlType
import Database.Selda.Types
import Control.Exception
import Data.Monoid
import System.IO.Unsafe
data SqlSource
= TableName !TableName
| Product ![SQL]
| Join !JoinType !(Exp Bool) !SQL !SQL
| Values ![SomeCol] ![[Param]]
| EmptyTable
data JoinType = InnerJoin | LeftJoin
data SQL = SQL
{ cols :: ![SomeCol]
, source :: !SqlSource
, restricts :: ![Exp Bool]
, groups :: ![SomeCol]
, ordering :: ![(Order, SomeCol)]
, limits :: !(Maybe (Int, Int))
}
data Order = Asc | Desc
deriving (Show, Ord, Eq)
data Param where
Param :: !(Lit a) -> Param
instance Show Param where
show (Param l) = "Param " <> show l
instance Eq Param where
Param a == Param b = compLit a b == EQ
instance Ord Param where
compare (Param a) (Param b) = compLit a b
data DefaultValueException = DefaultValueException
deriving Show
instance Exception DefaultValueException
class Insert a where
params :: a -> [Either Param Param]
instance (SqlType a, Insert b) => Insert (a :*: b) where
params (a :*: b) = unsafePerformIO $ do
res <- try $ return $! a
return $ case res of
Right a' ->
Right (Param (mkLit a')) : params b
Left DefaultValueException ->
Left (Param (defaultValue :: Lit a)) : params b
instance SqlType a => Insert a where
params a = unsafePerformIO $ do
res <- try $ return $! a
return $ case res of
Right a' ->
[Right $ Param (mkLit a')]
Left DefaultValueException ->
[Left $ Param (defaultValue :: Lit a)]