ghc-mod/Language/Haskell/GhcMod/Convert.hs

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{-# LANGUAGE FlexibleInstances, FlexibleContexts, OverlappingInstances #-}
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module Language.Haskell.GhcMod.Convert (convert, convert', emptyResult, whenFound, whenFound') where
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import Language.Haskell.GhcMod.Monad
import Language.Haskell.GhcMod.Types
import Control.Applicative ((<$>))
type Builder = String -> String
-- |
--
-- >>> replace '"' "\\\"" "foo\"bar" ""
-- "foo\\\"bar"
replace :: Char -> String -> String -> Builder
replace _ _ [] = id
replace c cs (x:xs)
| x == c = (cs ++) . replace c cs xs
| otherwise = (x :) . replace c cs xs
inter :: Char -> [Builder] -> Builder
inter _ [] = id
inter c bs = foldr1 (\x y -> x . (c:) . y) bs
convert' :: ToString a => a -> GhcMod String
convert' x = flip convert x <$> options
convert :: ToString a => Options -> a -> String
convert opt@Options { outputStyle = LispStyle } x = toLisp opt x "\n"
convert opt@Options { outputStyle = PlainStyle } x
| str == "\n" = ""
| otherwise = str
where
str = toPlain opt x "\n"
class ToString a where
toLisp :: Options -> a -> Builder
toPlain :: Options -> a -> Builder
lineSep :: Options -> String
lineSep opt = lsep
where
LineSeparator lsep = lineSeparator opt
-- |
--
-- >>> toLisp defaultOptions "fo\"o" ""
-- "\"fo\\\"o\""
-- >>> toPlain defaultOptions "foo" ""
-- "foo"
instance ToString String where
toLisp opt = quote opt
toPlain opt = replace '\n' (lineSep opt)
-- |
--
-- >>> toLisp defaultOptions ["foo", "bar", "ba\"z"] ""
-- "(\"foo\" \"bar\" \"ba\\\"z\")"
-- >>> toPlain defaultOptions ["foo", "bar", "baz"] ""
-- "foo\nbar\nbaz"
instance ToString [String] where
toLisp opt = toSexp1 opt
toPlain opt = inter '\n' . map (toPlain opt)
-- |
--
-- >>> let inp = [((1,2,3,4),"foo"),((5,6,7,8),"bar")] :: [((Int,Int,Int,Int),String)]
-- >>> toLisp defaultOptions inp ""
-- "((1 2 3 4 \"foo\") (5 6 7 8 \"bar\"))"
-- >>> toPlain defaultOptions inp ""
-- "1 2 3 4 \"foo\"\n5 6 7 8 \"bar\""
instance ToString [((Int,Int,Int,Int),String)] where
toLisp opt = toSexp2 . map toS
where
toS x = ('(' :) . tupToString opt x . (')' :)
toPlain opt = inter '\n' . map (tupToString opt)
instance ToString ((Int,Int,Int,Int),String) where
toLisp opt x = ('(' :) . tupToString opt x . (')' :)
toPlain opt x = tupToString opt x
instance ToString (String, (Int,Int,Int,Int),[String]) where
toLisp opt (s,x,y) = toSexp2 $ [toLisp opt s, ('(' :) . fourIntsToString opt x . (')' :), toLisp opt y]
toPlain opt (s,x,y) = inter '\n' [toPlain opt s, fourIntsToString opt x, toPlain opt y]
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toSexp1 :: Options -> [String] -> Builder
toSexp1 opt ss = ('(' :) . inter ' ' (map (quote opt) ss) . (')' :)
toSexp2 :: [Builder] -> Builder
toSexp2 ss = ('(' :) . (inter ' ' ss) . (')' :)
fourIntsToString :: Options -> (Int,Int,Int,Int) -> Builder
fourIntsToString _ (a,b,c,d) = (show a ++) . (' ' :)
. (show b ++) . (' ' :)
. (show c ++) . (' ' :)
. (show d ++)
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tupToString :: Options -> ((Int,Int,Int,Int),String) -> Builder
tupToString opt ((a,b,c,d),s) = (show a ++) . (' ' :)
. (show b ++) . (' ' :)
. (show c ++) . (' ' :)
. (show d ++) . (' ' :)
. quote opt s -- fixme: quote is not necessary
quote :: Options -> String -> Builder
quote opt str = ("\"" ++) . (quote' str ++) . ("\"" ++)
where
lsep = lineSep opt
quote' [] = []
quote' (x:xs)
| x == '\n' = lsep ++ quote' xs
| x == '\\' = "\\\\" ++ quote' xs
| x == '"' = "\\\"" ++ quote' xs
| otherwise = x : quote' xs
----------------------------------------------------------------
-- Empty result to be returned when no info can be gathered
emptyResult :: Monad m => Options -> m String
emptyResult opt = return $ convert opt ([] :: [String])
-- Return an emptyResult when Nothing
whenFound :: (Monad m, ToString b) => Options -> m (Maybe a) -> (a -> b) -> m String
whenFound opt from f = maybe (emptyResult opt) (return . convert opt . f) =<< from
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-- Return an emptyResult when Nothing, inside a monad
whenFound' :: (Monad m, ToString b) => Options -> m (Maybe a) -> (a -> m b) -> m String
whenFound' opt from f = maybe (emptyResult opt) (\x -> do y <- f x ; return (convert opt y)) =<< from