module Hint.Import where
import Hint.Type
import Util
import Data.Maybe
importHint :: ModuHint
importHint _ x = concatMap (wrap . snd) (groupSortFst
[((fromNamed $ importModule i,importPkg i),i) | i <- universeBi x, not $ importSrc i]) ++
concatMap hierarchy (universeBi x)
wrap :: [ImportDecl S] -> [Idea]
wrap o = [ rawIdea Error "Use fewer imports" (toSrcLoc $ ann $ head o) (f o) (f x)
| Just x <- [simplify o]]
where f = unlines . map prettyPrint
simplify :: [ImportDecl S] -> Maybe [ImportDecl S]
simplify [] = Nothing
simplify (x:xs) = case simplifyHead x xs of
Nothing -> fmap (x:) $ simplify xs
Just xs -> Just $ fromMaybe xs $ simplify xs
simplifyHead :: ImportDecl S -> [ImportDecl S] -> Maybe [ImportDecl S]
simplifyHead x [] = Nothing
simplifyHead x (y:ys) = case reduce x y of
Nothing -> fmap (y:) $ simplifyHead x ys
Just xy -> Just $ xy : ys
reduce :: ImportDecl S -> ImportDecl S -> Maybe (ImportDecl S)
reduce x y | qual, as, specs = Just x
| qual, as, Just (ImportSpecList _ False xs) <- importSpecs x, Just (ImportSpecList _ False ys) <- importSpecs y =
Just x{importSpecs = Just $ ImportSpecList an False $ nub_ $ xs ++ ys}
| qual, as, isNothing (importSpecs x) || isNothing (importSpecs y) = Just x{importSpecs=Nothing}
| not (importQualified x), qual, specs, length ass == 1 = Just x{importAs=Just $ head ass}
where
qual = importQualified x == importQualified y
as = importAs x `eqMaybe` importAs y
ass = mapMaybe importAs [x,y]
specs = importSpecs x `eqMaybe` importSpecs y
reduce _ _ = Nothing
newNames = let (*) = flip (,) in
["Control" * "Monad"
,"Data" * "Char"
,"Data" * "List"
,"Data" * "Maybe"
,"Data" * "Ratio"
,"System" * "Directory"
,"System" * "IO"
]
hierarchy :: ImportDecl S -> [Idea]
hierarchy i@ImportDecl{importModule=ModuleName _ x} | Just y <- lookup x newNames
= [warn "Use hierarchical imports" i i{importModule=ModuleName an $ y ++ "." ++ x}]
hierarchy _ = []