ghc-mod/Language/Haskell/GhcMod/Convert.hs
Daniel Gröber f0bfcb8811 Use GhcModT everywhere and remove the GhcMod alias
Not doing this makes having GhcModT pretty pointless as users of the
library wouldn't be able to use custom inner monads as evey function for
dealing with GhcModT's would be constraint to (GhcModT IO) thus only
allowing IO as the inner monad.
2014-07-15 01:03:56 +02:00

130 lines
4.3 KiB
Haskell

{-# LANGUAGE FlexibleInstances, FlexibleContexts, OverlappingInstances #-}
module Language.Haskell.GhcMod.Convert (convert, convert', emptyResult, whenFound, whenFound') where
import Language.Haskell.GhcMod.Monad
import Language.Haskell.GhcMod.Types
import Control.Applicative ((<$>))
type Builder = String -> String
-- |
--
-- >>> replace '"' "\\\"" "foo\"bar" ""
-- "foo\\\"bar"
replace :: Char -> String -> String -> Builder
replace _ _ [] = id
replace c cs (x:xs)
| x == c = (cs ++) . replace c cs xs
| otherwise = (x :) . replace c cs xs
inter :: Char -> [Builder] -> Builder
inter _ [] = id
inter c bs = foldr1 (\x y -> x . (c:) . y) bs
convert' :: (ToString a, IOish m) => a -> GhcModT m String
convert' x = flip convert x <$> 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]
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 ++)
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
-- 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