|
| 1 | +{-# LANGUAGE |
| 2 | + GeneralizedNewtypeDeriving |
| 3 | + , FlexibleInstances |
| 4 | + #-} |
| 5 | + |
| 6 | +module Data.Uri.Query where |
| 7 | + |
| 8 | + |
| 9 | +import qualified Data.Attoparsec.Text as Atto (Parser, parseOnly) |
| 10 | +import qualified Data.Aeson as Aeson (FromJSON, decode) |
| 11 | +import Network.HTTP.Types.URI |
| 12 | + |
| 13 | +import Data.ByteString as BS |
| 14 | +import Data.Text as T |
| 15 | +import Data.Text.Encoding as T |
| 16 | +import Data.Text.Lazy as LT |
| 17 | +import Data.Text.Lazy.Encoding as LT |
| 18 | +import Data.Functor.Identity |
| 19 | +import Data.String (IsString (fromString)) |
| 20 | +import Control.Applicative |
| 21 | +import Control.Monad.State |
| 22 | +import Control.Monad.Except |
| 23 | +import Control.Error (hush) |
| 24 | + |
| 25 | + |
| 26 | + |
| 27 | +data ParserState = ParserState |
| 28 | + { parserStateSoFar :: [(T.Text, Maybe T.Text)] |
| 29 | + , parserStateToParse :: [(T.Text, Maybe T.Text)] |
| 30 | + } deriving (Show, Eq) |
| 31 | + |
| 32 | + |
| 33 | +initParserState :: [(T.Text, Maybe T.Text)] -> ParserState |
| 34 | +initParserState xs = ParserState |
| 35 | + { parserStateSoFar = [] |
| 36 | + , parserStateToParse = xs |
| 37 | + } |
| 38 | + |
| 39 | + |
| 40 | +data ParserError |
| 41 | + = NoParse |
| 42 | + |
| 43 | + |
| 44 | + |
| 45 | +newtype Parser a = Parser |
| 46 | + { getParser :: StateT ParserState (ExceptT ParserError Identity) a |
| 47 | + } deriving (Functor, Applicative, Monad) |
| 48 | + |
| 49 | + |
| 50 | +runParser :: Parser a -> [(T.Text, Maybe T.Text)] -> Either ParserError a |
| 51 | +runParser p xs = fst <$> runParser' p (initParserState xs) |
| 52 | + |
| 53 | + |
| 54 | +runParser' :: Parser a -> ParserState -> Either ParserError (a, ParserState) |
| 55 | +runParser' (Parser p) = |
| 56 | + runIdentity . runExceptT . runStateT p |
| 57 | + |
| 58 | + |
| 59 | +instance Alternative Parser where |
| 60 | + empty = Parser $ StateT $ \_ -> throwError NoParse |
| 61 | + x <|> y = Parser $ do |
| 62 | + s <- get |
| 63 | + case runParser' x s of |
| 64 | + Right (x', s') -> do |
| 65 | + put s' |
| 66 | + pure x' |
| 67 | + Left _ -> |
| 68 | + case runParser' y s of |
| 69 | + Right (y', s') -> do |
| 70 | + put s' |
| 71 | + pure y' |
| 72 | + Left e -> throwError e |
| 73 | + |
| 74 | + |
| 75 | +unlabeled :: PieceParser a -> Parser a |
| 76 | +unlabeled (PieceParser f) = Parser $ do |
| 77 | + s <- get |
| 78 | + case parserStateToParse s of |
| 79 | + (x,x') : ss -> |
| 80 | + case f x of |
| 81 | + Nothing -> throwError NoParse |
| 82 | + Just y -> do put ParserState |
| 83 | + { parserStateSoFar = (x,x') : parserStateSoFar s |
| 84 | + , parserStateToParse = ss |
| 85 | + } |
| 86 | + pure y |
| 87 | + _ -> throwError NoParse |
| 88 | + |
| 89 | + |
| 90 | +-- | Useless label |
| 91 | +(.=) :: PieceParser a -> PieceParser b -> Parser b |
| 92 | +(PieceParser l) .= (PieceParser f) = Parser $ do |
| 93 | + s <- get |
| 94 | + case parserStateToParse s of |
| 95 | + (x,x') : ss -> |
| 96 | + case l x of |
| 97 | + Nothing -> throwError NoParse |
| 98 | + Just _ -> |
| 99 | + case f =<< x' of |
| 100 | + Nothing -> throwError NoParse |
| 101 | + Just y -> do put ParserState |
| 102 | + { parserStateSoFar = (x,x') : parserStateSoFar s |
| 103 | + , parserStateToParse = ss |
| 104 | + } |
| 105 | + pure y |
| 106 | + _ -> throwError NoParse |
| 107 | + |
| 108 | + |
| 109 | +overEquals :: (a -> b -> c) -> PieceParser a -> PieceParser b -> Parser c |
| 110 | +overEquals f (PieceParser l) (PieceParser r) = Parser $ do |
| 111 | + s <- get |
| 112 | + case parserStateToParse s of |
| 113 | + (x,x') : ss -> |
| 114 | + case l x of |
| 115 | + Nothing -> throwError NoParse |
| 116 | + Just l' -> |
| 117 | + case r =<< x' of |
| 118 | + Nothing -> throwError NoParse |
| 119 | + Just r' -> do put ParserState |
| 120 | + { parserStateSoFar = (x,x') : parserStateSoFar s |
| 121 | + , parserStateToParse = ss |
| 122 | + } |
| 123 | + pure (f l' r') |
| 124 | + _ -> throwError NoParse |
| 125 | + |
| 126 | + |
| 127 | + |
| 128 | +-- * Pieces |
| 129 | + |
| 130 | +newtype PieceParser a = PieceParser |
| 131 | + { getPieceParser :: T.Text -> Maybe a |
| 132 | + } |
| 133 | + |
| 134 | +instance IsString (PieceParser T.Text) where |
| 135 | + fromString s = PieceParser $ \t -> t <$ guard (T.pack s == t) |
| 136 | + |
| 137 | +fromUtf8 :: (T.Text -> Maybe a) -> PieceParser a |
| 138 | +fromUtf8 = PieceParser |
| 139 | + |
| 140 | +attoparsec :: Atto.Parser a -> PieceParser a |
| 141 | +attoparsec p = fromUtf8 (hush . Atto.parseOnly p) |
| 142 | + |
| 143 | +aeson :: Aeson.FromJSON a => PieceParser a |
| 144 | +aeson = fromUtf8 (Aeson.decode . LT.encodeUtf8 . LT.fromStrict) |
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