From be5ec956471b139fa77195f3104b44e41b1d3ffe Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Sun, 7 Sep 2014 16:55:32 +0300
Subject: [PATCH] Clean up parsing module further

---
 yesod-routes/Yesod/Routes/TH/ParseRoute.hs | 175 ++-------------------
 1 file changed, 10 insertions(+), 165 deletions(-)

diff --git a/yesod-routes/Yesod/Routes/TH/ParseRoute.hs b/yesod-routes/Yesod/Routes/TH/ParseRoute.hs
index b1e6d55a..1a4c29a8 100644
--- a/yesod-routes/Yesod/Routes/TH/ParseRoute.hs
+++ b/yesod-routes/Yesod/Routes/TH/ParseRoute.hs
@@ -6,48 +6,9 @@ module Yesod.Routes.TH.ParseRoute
 
 import Yesod.Routes.TH.Types
 import Language.Haskell.TH.Syntax
-import Data.Text (Text, pack)
-import Web.PathPieces (PathPiece (..), PathMultiPiece (..))
+import Data.Text (Text)
 import Yesod.Routes.Class
 import Yesod.Routes.TH.Dispatch
-import Data.List (foldl')
-import Control.Applicative ((<$>))
-import Data.Maybe (catMaybes)
-import Control.Monad (forM)
-import Control.Monad (join)
-
-{- FIXME
--- | Clauses for the 'parseRoute' method.
-mkParseRouteClauses :: [ResourceTree a] -> Q [Clause]
-mkParseRouteClauses ress' = do
-    pieces <- newName "pieces0"
-    dispatch <- newName "dispatch"
-    query <- newName "_query"
-
-    -- The 'D.Route's used in the dispatch function
-    routes <- mapM (buildRoute query) ress
-
-    -- The dispatch function itself
-    toDispatch <- [|D.toDispatch|]
-    let dispatchFun = FunD dispatch
-            [Clause
-                []
-                (NormalB $ toDispatch `AppE` ListE routes)
-                []
-            ]
-
-    join' <- [|join|]
-    let body = join' `AppE` (VarE dispatch `AppE` VarE pieces)
-    return $ return $ Clause
-        [TupP [VarP pieces, VarP query]]
-        (NormalB body)
-        [dispatchFun]
-  where
-    ress = map noMethods $ flatten ress'
-    noMethods (FlatResource a b c d e) = FlatResource a b c (noMethods' d) e
-    noMethods' (Methods a _) = Methods a []
-    noMethods' (Subsite a b) = Subsite a b
--}
 
 mkParseRouteInstance :: Type -> [ResourceTree a] -> Q Dec
 mkParseRouteInstance typ ress = do
@@ -57,12 +18,12 @@ mkParseRouteInstance typ ress = do
             , mds404 = [|error "mds404"|]
             , mds405 = [|error "mds405"|]
             , mdsGetPathInfo = [|fst|]
-            , mdsMethod = [|const ("GET" :: Text)|] -- FIXME wouldn't it be nice to get rid of method dispatching here
+            , mdsMethod = [|error "mdsMethod"|]
             , mdsGetHandler = \_ _ -> [|error "mdsGetHandler"|]
             , mdsSetPathInfo = [|\p (_, q) -> (p, q)|]
-            , mdsSubDispatcher = [|\_runHandler _getSub toMaster _env (p, q) -> fmap toMaster (parseRoute (p :: [Text], q :: [(Text, Text)]))|]
+            , mdsSubDispatcher = [|\_runHandler _getSub toMaster _env -> fmap toMaster . parseRoute|]
             }
-        ress
+        (map removeMethods ress)
     helper <- newName "helper"
     fixer <- [|(\f x -> f () x) :: (() -> ([Text], [(Text, Text)]) -> Maybe (Route a)) -> ([Text], [(Text, Text)]) -> Maybe (Route a)|]
     return $ InstanceD [] (ConT ''ParseRoute `AppT` typ)
@@ -71,128 +32,12 @@ mkParseRouteInstance typ ress = do
             (NormalB $ fixer `AppE` VarE helper)
             [FunD helper [cls]]
         ]
-        {- FIXME
-
--- | Build a single 'D.Route' expression.
-buildRoute :: Name -> FlatResource a -> Q Exp
-buildRoute query (FlatResource parents name resPieces resDisp _check) = do
-    -- First two arguments to D.Route
-    routePieces <- ListE <$> mapM convertPiece allPieces
-    isMulti <-
-        case resDisp of
-            Methods Nothing _ -> [|False|]
-            _ -> [|True|]
-
-    [|D.Route
-        $(return routePieces)
-        $(return isMulti)
-        $(routeArg3
-            query
-            parents
-            name
-            allPieces
-            resDisp)
-        |]
   where
-    allPieces = concat $ map snd parents ++ [resPieces]
+    -- We do this in order to ski the unnecessary method parsing
+    removeMethods (ResourceLeaf res) = ResourceLeaf $ removeMethodsLeaf res
+    removeMethods (ResourceParent w x y z) = ResourceParent w x y $ map removeMethods z
 
-routeArg3 :: Name -- ^ query string parameters
-          -> [(String, [Piece a])]
-          -> String -- ^ name of resource
-          -> [Piece a]
-          -> Dispatch a
-          -> Q Exp
-routeArg3 query parents name resPieces resDisp = do
-    pieces <- newName "pieces"
+    removeMethodsLeaf res = res { resourceDispatch = fixDispatch $ resourceDispatch res }
 
-    -- Allocate input piece variables (xs) and variables that have been
-    -- converted via fromPathPiece (ys)
-    xs <- forM resPieces $ \piece ->
-        case piece of
-            Static _ -> return Nothing
-            Dynamic _ -> Just <$> newName "x"
-
-    -- Note: the zipping with Ints is just a workaround for (apparently) a bug
-    -- in GHC where the identifiers are considered to be overlapping. Using
-    -- newName should avoid the problem, but it doesn't.
-    ys <- forM (zip (catMaybes xs) [1..]) $ \(x, i) -> do
-        y <- newName $ "y" ++ show (i :: Int)
-        return (x, y)
-
-    -- In case we have multi pieces at the end
-    xrest <- newName "xrest"
-    yrest <- newName "yrest"
-
-    -- Determine the pattern for matching the pieces
-    pat <-
-        case resDisp of
-            Methods Nothing _ -> return $ ListP $ map (maybe WildP VarP) xs
-            _ -> do
-                let cons = mkName ":"
-                return $ foldr (\a b -> ConP cons [maybe WildP VarP a, b]) (VarP xrest) xs
-
-    -- Convert the xs
-    fromPathPiece' <- [|fromPathPiece|]
-    xstmts <- forM ys $ \(x, y) -> return $ BindS (VarP y) (fromPathPiece' `AppE` VarE x)
-
-    -- Convert the xrest if appropriate
-    (reststmts, yrest') <-
-        case resDisp of
-            Methods (Just _) _ -> do
-                fromPathMultiPiece' <- [|fromPathMultiPiece|]
-                return ([BindS (VarP yrest) (fromPathMultiPiece' `AppE` VarE xrest)], [yrest])
-            _ -> return ([], [])
-
-    -- The final expression that actually uses the values we've computed
-    caller <- buildCaller query xrest parents name resDisp $ map snd ys ++ yrest'
-
-    -- Put together all the statements
-    just <- [|Just|]
-    let stmts = concat
-            [ xstmts
-            , reststmts
-            , [NoBindS $ just `AppE` caller]
-            ]
-
-    errorMsg <- [|error "Invariant violated"|]
-    let matches =
-            [ Match pat (NormalB $ DoE stmts) []
-            , Match WildP (NormalB errorMsg) []
-            ]
-
-    return $ LamE [VarP pieces] $ CaseE (VarE pieces) matches
-
--- | The final expression in the individual Route definitions.
-buildCaller :: Name -- ^ query string parameters
-            -> Name -- ^ xrest
-            -> [(String, [Piece a])]
-            -> String -- ^ name of resource
-            -> Dispatch a
-            -> [Name] -- ^ ys
-            -> Q Exp
-buildCaller query xrest parents name resDisp ys = do
-    -- Create the route
-    let route = routeFromDynamics parents name ys
-
-    case resDisp of
-        Methods _ _ -> [|Just $(return route)|]
-        Subsite _ _ -> [|fmap $(return route) $ parseRoute ($(return $ VarE xrest), $(return $ VarE query))|]
-
--- | Convert a 'Piece' to a 'D.Piece'
-convertPiece :: Piece a -> Q Exp
-convertPiece (Static s) = [|D.Static (pack $(lift s))|]
-convertPiece (Dynamic _) = [|D.Dynamic|]
-
-routeFromDynamics :: [(String, [Piece a])] -- ^ parents
-                  -> String -- ^ constructor name
-                  -> [Name]
-                  -> Exp
-routeFromDynamics [] name ys = foldl' (\a b -> a `AppE` VarE b) (ConE $ mkName name) ys
-routeFromDynamics ((parent, pieces):rest) name ys =
-    foldl' (\a b -> a `AppE` b) (ConE $ mkName parent) here
-  where
-    (here', ys') = splitAt (length $ filter isDynamic pieces) ys
-    isDynamic Dynamic{} = True
-    isDynamic _ = False
-    here = map VarE here' ++ [routeFromDynamics rest name ys']
--}
+    fixDispatch (Methods x _) = Methods x []
+    fixDispatch x = x