TH.hs

module Hasql.TH
(
  readFileAsSQL,
)
where

import Hasql.TH.Prelude
import Language.Haskell.TH.Syntax
import qualified Hasql.TH.Renderers as Renderers
import qualified Data.ByteString


-- |
-- Read an SQL-file, containing multiple statements,
-- and produce an expression of type `ByteString`.
-- 
-- Allows to store plain SQL in external files and read it at compile time.
-- 
-- E.g.,
-- 
-- >migration1 :: Hasql.Session.Session ()
-- >migration1 =
-- >  Hasql.Session.sql $(Hasql.TH.readFileAsSQL "sql/migration-1.sql")
-- 
readFileAsSQL :: String -> Q Exp
readFileAsSQL =
  fmap Renderers.byteStringExp . readFileAsBytes

readFileAsBytes :: String -> Q ByteString
readFileAsBytes =
  (*>) <$> addDependentFile <*> runIO . Data.ByteString.readFile