{-# LANGUAGE TemplateHaskell #-} module Text.Hamlet.Quasi ( hamlet , xhamlet , hamletWithSettings ) where import Text.Hamlet.Parse import Language.Haskell.TH.Syntax import Language.Haskell.TH.Quote import Data.Char (isUpper) import qualified Data.ByteString.UTF8 as BSU import qualified Data.ByteString.Char8 as S8 import Data.Monoid (mconcat, mappend, mempty) import Text.Blaze (unsafeByteString, Html, string) import Data.List (intercalate) type Scope = [(Ident, Exp)] docsToExp :: Exp -> Scope -> [Doc] -> Q Exp docsToExp render scope docs = do exps <- mapM (docToExp render scope) docs ma <- [|mappend|] me <- [|mempty|] return $ if null exps then me else foldr1 (go ma) exps where go ma x y = ma `AppE` x `AppE` y docToExp :: Exp -> Scope -> Doc -> Q Exp docToExp render scope (DocForall list ident@(Ident name) inside) = do let list' = deref scope list name' <- newName name let scope' = (ident, VarE name') : scope mh <- [|\a -> mconcat . map a|] inside' <- docsToExp render scope' inside let lam = LamE [VarP name'] inside' return $ mh `AppE` lam `AppE` list' docToExp render scope (DocMaybe val ident@(Ident name) inside mno) = do let val' = deref scope val name' <- newName name let scope' = (ident, VarE name') : scope inside' <- docsToExp render scope' inside let inside'' = LamE [VarP name'] inside' ninside' <- case mno of Nothing -> [|Nothing|] Just no -> do no' <- docsToExp render scope no j <- [|Just|] return $ j `AppE` no' mh <- [|maybeH|] return $ mh `AppE` val' `AppE` inside'' `AppE` ninside' docToExp render scope (DocCond conds final) = do conds' <- mapM go conds final' <- case final of Nothing -> [|Nothing|] Just f -> do f' <- docsToExp render scope f j <- [|Just|] return $ j `AppE` f' ch <- [|condH|] return $ ch `AppE` ListE conds' `AppE` final' where go :: (Deref, [Doc]) -> Q Exp go (d, docs) = do let d' = deref scope d docs' <- docsToExp render scope docs return $ TupE [d', docs'] docToExp render v (DocContent c) = contentToExp render v c contentToExp :: Exp -> Scope -> Content -> Q Exp contentToExp _ _ (ContentRaw s) = do os <- [|unsafeByteString . S8.pack|] let s' = LitE $ StringL $ S8.unpack $ BSU.fromString s return $ os `AppE` s' contentToExp _ scope (ContentVar d) = return $ deref scope d contentToExp render scope (ContentUrl hasParams d) = do ou <- if hasParams then [|outputUrlParams|] else [|outputUrl|] let d' = deref scope d return $ ou `AppE` render `AppE` d' contentToExp render scope (ContentEmbed d) = do let d' = deref scope d return (d' `AppE` render) -- | Calls 'hamletWithSettings' with 'defaultHamletSettings'. hamlet :: QuasiQuoter hamlet = hamletWithSettings defaultHamletSettings -- | Calls 'hamletWithSettings' using XHTML 1.0 Strict settings. xhamlet :: QuasiQuoter xhamlet = hamletWithSettings $ HamletSettings doctype True where doctype = "" -- | A quasi-quoter that converts Hamlet syntax into a function of form: -- -- > (url -> String) -> Html -- -- Please see accompanying documentation for a description of Hamlet syntax. hamletWithSettings :: HamletSettings -> QuasiQuoter hamletWithSettings set = QuasiQuoter go $ error "Cannot quasi-quote Hamlet to patterns" where go s = do case parseDoc set s of Error s' -> error s' Ok d -> do render <- newName "_render" func <- docsToExp (VarE render) [] d return $ LamE [VarP render] func deref :: Scope -> Deref -> Exp deref _ (Deref []) = error "Invalid empty deref" deref scope (Deref (z@(Ident zName):y)) = let z' = case lookup z scope of Nothing -> varName zName Just zExp -> zExp in foldr go z' $ reverse y where varName "" = error "Illegal empty varName" varName v@(s:_) = case lookup (Ident v) scope of Just e -> e Nothing -> if isUpper s then ConE $ mkName v else VarE $ mkName v go (Ident func) z' = varName func `AppE` z' -- | Checks for truth in the left value in each pair in the first argument. If -- a true exists, then the corresponding right action is performed. Only the -- first is performed. In there are no true values, then the second argument is -- performed, if supplied. condH :: [(Bool, Html ())] -> Maybe (Html ()) -> Html () condH [] Nothing = mempty condH [] (Just x) = x condH ((True, y):_) _ = y condH ((False, _):rest) z = condH rest z -- | Runs the second argument with the value in the first, if available. -- Otherwise, runs the third argument, if available. maybeH :: Maybe v -> (v -> Html ()) -> Maybe (Html ()) -> Html () maybeH Nothing _ Nothing = mempty maybeH Nothing _ (Just x) = x maybeH (Just v) f _ = f v -- | Uses the URL rendering function to convert the given URL to a 'String' and -- then calls 'outputString'. outputUrl :: (url -> String) -> url -> Html () outputUrl render u = string $ render u -- | Same as 'outputUrl', but appends a query-string with given keys and -- values. outputUrlParams :: (url -> String) -> (url, [(String, String)]) -> Html () outputUrlParams render (u, []) = outputUrl render u outputUrlParams render (u, params) = mappend (outputUrl render u) (string $ showParams params) where showParams x = '?' : intercalate "&" (map go x) go (x, y) = go' x ++ '=' : go' y go' = concatMap encodeUrlChar -- | Taken straight from web-encodings; reimplemented here to avoid extra -- dependencies. encodeUrlChar :: Char -> String encodeUrlChar c -- List of unreserved characters per RFC 3986 -- Gleaned from http://en.wikipedia.org/wiki/Percent-encoding | 'A' <= c && c <= 'Z' = [c] | 'a' <= c && c <= 'z' = [c] | '0' <= c && c <= '9' = [c] encodeUrlChar c@'-' = [c] encodeUrlChar c@'_' = [c] encodeUrlChar c@'.' = [c] encodeUrlChar c@'~' = [c] encodeUrlChar ' ' = "+" encodeUrlChar y = let (a, c) = fromEnum y `divMod` 16 b = a `mod` 16 showHex' x | x < 10 = toEnum $ x + (fromEnum '0') | x < 16 = toEnum $ x - 10 + (fromEnum 'A') | otherwise = error $ "Invalid argument to showHex: " ++ show x in ['%', showHex' b, showHex' c]