module Yesod.Routes.TH.RenderRoute
(
mkRenderRouteInstance
, mkRouteCons
, mkRenderRouteClauses
) where
import Yesod.Routes.TH.Types
import Language.Haskell.TH.Syntax
import Data.Maybe (maybeToList)
import Control.Monad (replicateM)
import Data.Text (pack)
import Web.PathPieces (PathPiece (..), PathMultiPiece (..))
import Yesod.Routes.Class
mkRouteCons :: [Resource Type] -> [Con]
mkRouteCons =
map mkRouteCon
where
mkRouteCon res =
NormalC (mkName $ resourceName res)
$ map (\x -> (NotStrict, x))
$ concat [singles, multi, sub]
where
singles = concatMap (toSingle . snd) $ resourcePieces res
toSingle Static{} = []
toSingle (Dynamic typ) = [typ]
multi = maybeToList $ resourceMulti res
sub =
case resourceDispatch res of
Subsite { subsiteType = typ } -> [ConT ''Route `AppT` typ]
_ -> []
mkRenderRouteClauses :: [Resource Type] -> Q [Clause]
mkRenderRouteClauses =
mapM go
where
isDynamic Dynamic{} = True
isDynamic _ = False
go res = do
let cnt = length (filter (isDynamic . snd) $ resourcePieces res) + maybe 0 (const 1) (resourceMulti res)
dyns <- replicateM cnt $ newName "dyn"
sub <-
case resourceDispatch res of
Subsite{} -> fmap return $ newName "sub"
_ -> return []
let pat = ConP (mkName $ resourceName res) $ map VarP $ dyns ++ sub
pack' <- [|pack|]
tsp <- [|toPathPiece|]
let piecesSingle = mkPieces (AppE pack' . LitE . StringL) tsp (map snd $ resourcePieces res) dyns
piecesMulti <-
case resourceMulti res of
Nothing -> return $ ListE []
Just{} -> do
tmp <- [|toPathMultiPiece|]
return $ tmp `AppE` VarE (last dyns)
body <-
case sub of
[x] -> do
rr <- [|renderRoute|]
a <- newName "a"
b <- newName "b"
colon <- [|(:)|]
let cons y ys = InfixE (Just y) colon (Just ys)
let pieces = foldr cons (VarE a) piecesSingle
return $ LamE [TupP [VarP a, VarP b]] (TupE [pieces, VarE b]) `AppE` (rr `AppE` VarE x)
_ -> do
colon <- [|(:)|]
let cons a b = InfixE (Just a) colon (Just b)
return $ TupE [foldr cons piecesMulti piecesSingle, ListE []]
return $ Clause [pat] (NormalB body) []
mkPieces _ _ [] _ = []
mkPieces toText tsp (Static s:ps) dyns = toText s : mkPieces toText tsp ps dyns
mkPieces toText tsp (Dynamic{}:ps) (d:dyns) = tsp `AppE` VarE d : mkPieces toText tsp ps dyns
mkPieces _ _ ((Dynamic _) : _) [] = error "mkPieces 120"
mkRenderRouteInstance :: Type -> [Resource Type] -> Q Dec
mkRenderRouteInstance typ ress = do
cls <- mkRenderRouteClauses ress
return $ InstanceD [] (ConT ''RenderRoute `AppT` typ)
[ DataInstD [] ''Route [typ] (mkRouteCons ress) clazzes
, FunD (mkName "renderRoute") cls
]
where
clazzes = [''Show, ''Eq, ''Read]