dhall-haskell/dhall/src/Dhall/Parser/Combinators.hs

260 lines
7.7 KiB
Haskell

{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
module Dhall.Parser.Combinators where
import Control.Applicative (Alternative (..), liftA2)
import Control.Exception (Exception)
import Control.Monad (MonadPlus (..))
import Data.Semigroup (Semigroup (..))
import Data.String (IsString (..))
import Data.Text (Text)
import Data.Text.Prettyprint.Doc (Pretty (..))
import Data.Void (Void)
import Dhall.Map (Map)
import Dhall.Set (Set)
import Dhall.Src (Src(..))
import Prelude hiding (const, pi)
import Text.Parser.Combinators (try, (<?>))
import Text.Parser.Token (TokenParsing (..))
import qualified Control.Monad.Fail
import qualified Data.Char
import qualified Data.Set
import qualified Data.Text
import qualified Data.Text.Prettyprint.Doc.Render.String as Pretty
import qualified Dhall.Map
import qualified Dhall.Pretty
import qualified Dhall.Set
import qualified Text.Megaparsec
import qualified Text.Megaparsec.Char
import qualified Text.Parser.Char
import qualified Text.Parser.Combinators
import qualified Text.Parser.Token.Style
-- | An exception annotated with a `Src` span
data SourcedException e = SourcedException Src e
instance Exception e => Exception (SourcedException e)
instance Show e => Show (SourcedException e) where
show (SourcedException source exception) =
show exception
<> "\n"
<> "\n"
<> Pretty.renderString
(Dhall.Pretty.layout (pretty source))
-- | Doesn't force the 'Text' part
laxSrcEq :: Src -> Src -> Bool
laxSrcEq (Src p q _) (Src p' q' _) = eq p p' && eq q q'
where
-- Don't compare filename (which is FilePath = String)
eq :: Text.Megaparsec.SourcePos -> Text.Megaparsec.SourcePos -> Bool
eq (Text.Megaparsec.SourcePos _ a b) (Text.Megaparsec.SourcePos _ a' b') =
a == a' && b == b'
{-# INLINE laxSrcEq #-}
{-| A `Parser` that is almost identical to
@"Text.Megaparsec".`Text.Megaparsec.Parsec`@ except treating Haskell-style
comments as whitespace
-}
newtype Parser a = Parser { unParser :: Text.Megaparsec.Parsec Void Text a }
instance Functor Parser where
fmap f (Parser x) = Parser (fmap f x)
{-# INLINE fmap #-}
f <$ Parser x = Parser (f <$ x)
{-# INLINE (<$) #-}
instance Applicative Parser where
pure = Parser . pure
{-# INLINE pure #-}
Parser f <*> Parser x = Parser (f <*> x)
{-# INLINE (<*>) #-}
Parser a <* Parser b = Parser (a <* b)
{-# INLINE (<*) #-}
Parser a *> Parser b = Parser (a *> b)
{-# INLINE (*>) #-}
instance Monad Parser where
return = pure
{-# INLINE return #-}
(>>) = (*>)
{-# INLINE (>>) #-}
Parser n >>= k = Parser (n >>= unParser . k)
{-# INLINE (>>=) #-}
#if !(MIN_VERSION_base(4,13,0))
fail = Control.Monad.Fail.fail
{-# INLINE fail #-}
#endif
instance Control.Monad.Fail.MonadFail Parser where
fail = Parser . Control.Monad.Fail.fail
{-# INLINE fail #-}
instance Alternative Parser where
empty = Parser empty
-- {-# INLINE empty #-}
Parser a <|> Parser b = Parser (a <|> b)
-- {-# INLINE (<|>) #-}
some (Parser a) = Parser (some a)
-- {-# INLINE some #-}
many (Parser a) = Parser (many a)
-- {-# INLINE many #-}
instance MonadPlus Parser where
mzero = empty
-- {-# INLINE mzero #-}
mplus = (<|>)
-- {-# INLINE mplus #-}
instance Text.Megaparsec.MonadParsec Void Text Parser where
#if MIN_VERSION_megaparsec(8, 0, 0)
parseError e = Parser (Text.Megaparsec.parseError e)
#else
failure u e = Parser (Text.Megaparsec.failure u e)
fancyFailure e = Parser (Text.Megaparsec.fancyFailure e)
#endif
label l (Parser p) = Parser (Text.Megaparsec.label l p)
hidden (Parser p) = Parser (Text.Megaparsec.hidden p)
try (Parser p) = Parser (Text.Megaparsec.try p)
lookAhead (Parser p) = Parser (Text.Megaparsec.lookAhead p)
notFollowedBy (Parser p) = Parser (Text.Megaparsec.notFollowedBy p)
withRecovery e (Parser p) = Parser (Text.Megaparsec.withRecovery (unParser . e) p)
observing (Parser p) = Parser (Text.Megaparsec.observing p)
eof = Parser Text.Megaparsec.eof
token f e = Parser (Text.Megaparsec.token f e)
tokens f ts = Parser (Text.Megaparsec.tokens f ts)
takeWhileP s f = Parser (Text.Megaparsec.takeWhileP s f)
takeWhile1P s f = Parser (Text.Megaparsec.takeWhile1P s f)
takeP s n = Parser (Text.Megaparsec.takeP s n)
getParserState = Parser Text.Megaparsec.getParserState
{-# INLINE getParserState #-}
updateParserState f = Parser (Text.Megaparsec.updateParserState f)
instance Data.Semigroup.Semigroup a => Data.Semigroup.Semigroup (Parser a) where
(<>) = liftA2 (<>)
instance (Data.Semigroup.Semigroup a, Monoid a) => Monoid (Parser a) where
mempty = pure mempty
#if !(MIN_VERSION_base(4,11,0))
mappend = (<>)
#endif
instance IsString a => IsString (Parser a) where
fromString x = fromString x <$ Text.Megaparsec.Char.string (fromString x)
instance Text.Parser.Combinators.Parsing Parser where
try = Text.Megaparsec.try
(<?>) = (Text.Megaparsec.<?>)
skipMany = Text.Megaparsec.skipMany
skipSome = Text.Megaparsec.skipSome
unexpected = fail
eof = Parser Text.Megaparsec.eof
notFollowedBy = Text.Megaparsec.notFollowedBy
instance Text.Parser.Char.CharParsing Parser where
satisfy = Parser . Text.Megaparsec.satisfy
char = Text.Megaparsec.Char.char
notChar = Text.Megaparsec.Char.char
anyChar = Text.Megaparsec.anySingle
string = fmap Data.Text.unpack . Text.Megaparsec.Char.string . fromString
text = Text.Megaparsec.Char.string
instance TokenParsing Parser where
someSpace =
Text.Parser.Token.Style.buildSomeSpaceParser
(Parser (Text.Megaparsec.skipSome (Text.Megaparsec.satisfy Data.Char.isSpace)))
Text.Parser.Token.Style.haskellCommentStyle
highlight _ = id
semi = token (Text.Megaparsec.Char.char ';' <?> ";")
count :: (Semigroup a, Monoid a) => Int -> Parser a -> Parser a
count n parser = mconcat (replicate n parser)
range :: (Semigroup a, Monoid a) => Int -> Int -> Parser a -> Parser a
range minimumBound maximumMatches parser =
count minimumBound parser <> loop maximumMatches
where
loop 0 = mempty
loop n = (parser <> loop (n - 1)) <|> mempty
option :: (Alternative f, Monoid a) => f a -> f a
option p = p <|> pure mempty
star :: (Alternative f, Monoid a) => f a -> f a
star p = plus p <|> pure mempty
plus :: (Alternative f, Monoid a) => f a -> f a
plus p = mappend <$> p <*> star p
satisfy :: (Char -> Bool) -> Parser Text
satisfy = fmap Data.Text.singleton . Text.Parser.Char.satisfy
takeWhile :: (Char -> Bool) -> Parser Text
takeWhile predicate = Parser (Text.Megaparsec.takeWhileP Nothing predicate)
takeWhile1 :: (Char -> Bool) -> Parser Text
takeWhile1 predicate = Parser (Text.Megaparsec.takeWhile1P Nothing predicate)
noDuplicates :: Ord a => [a] -> Parser (Set a)
noDuplicates = go Dhall.Set.empty
where
go found [] = return found
go found (x:xs) =
if Data.Set.member x (Dhall.Set.toSet found)
then fail "Duplicate key"
else go (Dhall.Set.append x found) xs
toMap :: [(Text, a)] -> Parser (Map Text a)
toMap kvs = Dhall.Map.unorderedTraverseWithKey (\_k v -> v) m
where
m = Dhall.Map.fromListWithKey err (map (\(k, v) -> (k, pure v)) kvs)
err k _v1 _v2 = Text.Parser.Combinators.unexpected
("duplicate field: " ++ Data.Text.unpack k)