{-# LANGUAGE ViewPatterns #-} {- Raise an error if you are bracketing an atom, or are enclosed be a list bracket <TEST> -- expression bracket reduction yes = (f x) x -- @Warning f x x no = f (x x) yes = (foo) -- foo yes = (foo bar) -- @Warning foo bar yes = foo (bar) -- @Error bar yes = foo ((x x)) -- @Error (x x) yes = (f x) ||| y -- @Warning f x ||| y yes = if (f x) then y else z -- @Warning if f x then y else z yes = if x then (f y) else z -- @Warning if x then f y else z yes = (a foo) :: Int -- @Warning a foo :: Int yes = [(foo bar)] -- @Warning [foo bar] yes = foo ((x y), z) -- @Warning (x y, z) yes = C { f = (e h) } -- @Warning C {f = e h} yes = \ x -> (x && x) -- @Warning \x -> x && x no = \(x -> y) -> z yes = (`foo` (bar baz)) -- @Warning (`foo` bar baz) main = do f; (print x) -- @Warning do f print x -- type bracket reduction foo :: (Int -> Int) -> Int foo :: Int -> (Int -> Int) -- @Warning Int -> Int -> Int foo :: (Maybe Int) -> a -- @Warning Maybe Int -> a instance Named (DeclHead S) data Foo = Foo {foo :: (Maybe Foo)} -- @Warning foo :: Maybe Foo -- pattern bracket reduction foo (True) = 1 foo ((True)) = 1 -- @Error True -- dollar reduction tests no = groupFsts . sortFst $ mr yes = split "to" $ names -- split "to" names yes = white $ keysymbol -- white keysymbol yes = operator foo $ operator -- operator foo operator no = operator foo $ operator bar yes = return $ Record{a=b} -- return Record{a=b} -- $/bracket rotation tests yes = (b $ c d) ++ e -- b (c d) ++ e yes = (a b $ c d) ++ e -- a b (c d) ++ e no = (f . g $ a) ++ e no = quickCheck ((\h -> cySucc h == succ h) :: Hygiene -> Bool) foo = (case x of y -> z; q -> w) :: Int -- backup fixity resolution main = do a += b . c; return $ a . b -- annotations main = 1; {-# ANN module ("HLint: ignore Use camelCase" :: String) #-} main = 1; {-# ANN module (1 + (2)) #-} -- 2 </TEST> -} module Hint.Bracket(bracketHint) where import Hint.Type bracketHint :: DeclHint bracketHint _ _ x = concatMap (\x -> bracket True x ++ dollar x) (childrenBi (descendBi annotations x) :: [Exp_]) ++ concatMap (bracket False) (childrenBi x :: [Type_]) ++ concatMap (bracket False) (childrenBi x :: [Pat_]) ++ concatMap fieldDecl (childrenBi x) where -- Brackets at the roots of annotations are fine, so we strip them annotations :: Annotation S -> Annotation S annotations = descendBi $ \x -> case (x :: Exp_) of Paren _ x -> x x -> x bracket :: (Annotated a, Uniplate (a S), ExactP a, Pretty (a S), Brackets (a S)) => Bool -> a S -> [Idea] bracket bad = f Nothing where msg = "Redundant bracket" -- f (Maybe (index, parent, gen)) child f :: (Annotated a, Uniplate (a S), ExactP a, Pretty (a S), Brackets (a S)) => Maybe (Int,a S,a S -> a S) -> a S -> [Idea] f Just{} o@(remParen -> Just x) | isAtom x = err msg o x : g x f Nothing o@(remParen -> Just x) | bad = warn msg o x : g x f (Just (i,o,gen)) (remParen -> Just x) | not $ needBracket i o x = warn msg o (gen x) : g x f _ x = g x g :: (Annotated a, Uniplate (a S), ExactP a, Pretty (a S), Brackets (a S)) => a S -> [Idea] g o = concat [f (Just (i,o,gen)) x | (i,(x,gen)) <- zip [0..] $ holes o] fieldDecl :: FieldDecl S -> [Idea] fieldDecl o@(FieldDecl a b (UnBangedTy c (TyParen _ d))) = [warn "Redundant bracket" o (FieldDecl a b (UnBangedTy c d))] fieldDecl _ = [] dollar :: Exp_ -> [Idea] dollar = concatMap f . universe where msg = warn "Redundant $" f x = [msg x y | InfixApp _ a d b <- [x], opExp d ~= "$" ,let y = App an a b, not $ needBracket 0 y a, not $ needBracket 1 y b] ++ [msg x (t y) |(t, Paren _ (InfixApp _ a1 op1 a2)) <- splitInfix x ,opExp op1 ~= "$", isVar a1 || isApp a1 || isParen a1, not $ isAtom a2 ,let y = App an a1 (Paren an a2)] -- return both sides, and a way to put them together again splitInfix :: Exp_ -> [(Exp_ -> Exp_, Exp_)] splitInfix (InfixApp s a b c) = [(InfixApp s a b, c), (\a -> InfixApp s a b c, a)] splitInfix _ = []