hsfm/hacking/hsimport.hs

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Haskell
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import Data.List
import qualified Language.Haskell.Exts as HS
import HsImport
main :: IO ()
main = hsimport $ defaultConfig { prettyPrint = prettyPrint
, findImportPos = findImportPos }
where
prettyPrint :: HS.ImportDecl -> String
prettyPrint (HS.ImportDecl sloc modname qual _ _ mpkg mas mspec) =
"import " ++ (ifStr qual "qualified ") ++
(maybe "" (\pkg -> " \"" ++ pkg ++ "\" ") mpkg) ++
getMN modname ++ (maybe "" (\name -> " as " ++ getMN name) $ mas) ++
specprint mspec
specprint :: Maybe (Bool, [HS.ImportSpec]) -> String
specprint Nothing = ""
specprint (Just (False, xs))
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= "\n (\n" ++ printImportSpecs xs ++ " )"
specprint (Just (True, xs))
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= "\n hiding (\n" ++ printImportSpecs xs ++ " )"
printImportSpecs :: [HS.ImportSpec] -> String
printImportSpecs ins
= let (x:xs) = sort ins
in " " ++ printSpec x ++ "\n" ++ go xs
where
go [] = ""
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go [x'] = " , " ++ printSpec x' ++ "\n"
go (x':xs') = " , " ++ printSpec x' ++ "\n" ++ go xs'
printSpec :: HS.ImportSpec -> String
printSpec = HS.prettyPrint
findImportPos :: HS.ImportDecl -> [HS.ImportDecl] -> Maybe ImportPos
findImportPos _ [] = Nothing
findImportPos newImport currentImports = Just findPos
where
lastPos = After . last $ currentImports
findPos = let xs = takeWhile (\x -> (getMN $ HS.importModule x)
<
(getMN $ HS.importModule newImport)
)
. sort
$ currentImports
in if null xs then lastPos else After . last $ xs
ifStr :: Bool -> String -> String
ifStr True str = str
ifStr False _ = ""
getMN :: HS.ModuleName -> String
getMN (HS.ModuleName name) = name