yesod/yesod-routes/Yesod/Routes/TH/Dispatch.hs
2012-01-03 08:37:23 +02:00

101 lines
3.4 KiB
Haskell

{-# LANGUAGE TemplateHaskell #-}
module Yesod.Routes.TH.Dispatch
( -- ** Dispatch
mkDispatchClause
) where
import Yesod.Routes.TH.Types
import Language.Haskell.TH.Syntax
import Data.Maybe (maybeToList, catMaybes)
import Control.Monad (replicateM)
import Data.Text (pack)
import qualified Yesod.Routes.Dispatch as D
import qualified Data.Map as Map
import Data.Char (toLower)
import Web.PathPieces (PathPiece (..), PathMultiPiece (..))
import Yesod.Routes.Class
mkDispatchClause :: [Resource]
-> Q Clause
mkDispatchClause ress = do
u <- [|error "mkDispatchClause"|]
return $ Clause [] (NormalB u) []
{- FIXME
let routes = fmap ListE $ mapM toRoute ress
sub <- newName "sub"
mkey <- newName "mkey"
ts <- newName "ts"
master <- newName "master"
toMaster <- newName "toMaster"
let pats =
[ VarP sub
, VarP mkey
, VarP ts
, VarP master
, VarP toMaster
]
dispatch <- newName "dispatch"
body <- [|D.toDispatch $(routes)|]
return $ Clause
pats
(NormalB $ VarE dispatch `AppE` VarE ts `AppE` TupE (map VarE [sub, mkey, master, toMaster]))
[FunD dispatch [Clause [] (NormalB body) []]]
where
mkTsPattern :: [Piece] -> Maybe t -> Q ([Name], Maybe Name, Pat)
mkTsPattern pieces mmulti = do
end <-
case mmulti of
Nothing -> return (Nothing, ConP (mkName "[]") [])
Just{} -> do
end <- newName "end"
return (Just end, VarP end)
pieces' <- mapM go pieces
return (catMaybes $ map fst pieces', fst end, foldr (flip InfixP $ mkName ":") (snd end) $ map snd pieces')
where
go Static{} = return (Nothing, WildP)
go Dynamic{} = do
dyn <- newName "dyn"
return (Just dyn, VarP dyn)
-- | Convert a 'Piece' into a 'D.Piece'.
toPiece :: Piece -> Q Exp
toPiece (Static s) = [|D.Static $ pack $(lift s)|]
toPiece Dynamic{} = [|D.Dynamic|]
-- | Convert a 'Resource' into a 'D.Route'.
toRoute :: Resource -> Q Exp
toRoute res = do
let ps = fmap ListE $ mapM toPiece $ resourcePieces res
let m = maybe [|False|] (const [|True|]) $ resourceMulti res
case resourceDispatch res of
Methods mmulti mds -> do
let toPair m' = do
key <- [|pack $(lift m')|]
let value = VarE $ mkName $ map toLower m' ++ resourceName res
return $ TupE [key, value]
let handler =
if null mds
then [|Left $(return $ VarE $ mkName $ "handle" ++ resourceName res)|]
else [|Right $ Map.fromList $(fmap ListE $ mapM toPair mds)|]
sub <- newName "sub"
mkey <- newName "mkey"
(dyns, mend, tsPattern) <- mkTsPattern (resourcePieces res) mmulti
master <- newName "master"
toMaster <- newName "toMaster"
body <- [|$(toApp) $(handler)|]
let func = LamE
[ tsPattern
, TupP
[ VarP sub
, VarP mkey
, VarP master
, VarP toMaster
]
]
body
[|D.Route $(ps) $(m) $(return func)|]
Subsite _ func -> [|D.Route $(ps) $(m) $ $(toApp) $(return $ VarE $ mkName $ "handle" ++ resourceName res)|] -- FIXME
-}