implementation module yard
import StdTuple
-from StdClass import Eq
+import StdClass
+import StdString
+import StdList
+import StdInt
+from Data.List import intersperse
+from Text import instance Text String, class Text(concat)
import Data.Functor
+import Data.Either
import Control.Monad
import Control.Applicative
from Data.Func import $
+import Data.Void
+
+instance toString Error where
+ toString (PositionalError l c e) =
+ concat [toString l,":",toString c,": ",e, "\n"]
+ toString (Error e) = concat ["-:-: ", e, "\n"]
runParser :: (Parser a b) [a] -> (Either Error b, [a])
runParser (Parser f) i = f i
-
+
instance Functor (Parser a) where
- //fmap f m = liftM f m
- fmap g p = Parser \i -> case runParser p i of
- (Right r, rest) = (Right $ g r, rest)
- (Left e, rest) = (Left e, rest)
+ fmap f m = liftM f m
instance Applicative (Parser a) where
- pure a = Parser \i -> (Right a, i)
- //(<*>) sf p = ap sf p
- (<*>) pf p = Parser \i -> case runParser pf i of
- (Right f, rest) = runParser (fmap f p) rest
- (Left e, rest) = (Left e, rest)
+ pure a = Parser \i -> (Right a, i)
+ (<*>) sf p = ap sf p
instance Monad (Parser a) where
- bind p f = Parser \i -> case runParser p i of
- (Right r, rest) = runParser (f r) rest
- (Left e, rest) = (Left e, rest)
+ bind p f = Parser \i -> case runParser p i of
+ (Right r, rest) = runParser (f r) rest
+ (Left e, _) = (Left e, i)
-//some, many, optional and l
instance Alternative (Parser a) where
- empty = Parser \i -> (Left ParseException, i)
- (<|>) p1 p2 = Parser \i -> case runParser p1 i of
- (Right r, rest) = (Right r, rest)
- (Left _, rest) = runParser p2 i
+ empty = Parser \i -> (Left $ Error "" , i)
+ (<|>) p1 p2 = Parser \i -> case runParser p1 i of
+ (Right r, rest) = (Right r, rest)
+ (Left e1, rest) = case runParser p2 i of
+ (Left e2, rest) = (Left e2, i)
+ (Right r, rest) = (Right r, rest)
+
+//Try parser, if it fails decorate the error with the given String and position
+(<?>) :: (Parser a b) Error -> Parser a b
+(<?>) p e = Parser \i -> case runParser p i of
+ (Left e1, rest) = (Left e, rest)
+ (Right r, rest) = (Right r, rest)
fail :: Parser a b
fail = empty
top :: Parser a a
top = Parser \i -> case i of
- [] = (Left ParseException, [])
- [x:xs] = (Right x, xs)
+ [] = (Left $ Error "", [])
+ [x:xs] = (Right x, xs)
+
+peek :: Parser a a
+peek = Parser \i -> case i of
+ [] = (Left $ Error "", [])
+ [x:xs] = (Right x, [x:xs])
+
+(until) infix 2 :: (Parser a b) (Parser a c) -> Parser a [b]
+(until) p guard = try $ until` p guard []
+ where
+ until` :: (Parser a b) (Parser a c) [b] -> Parser a [b]
+ until` p guard acc = Parser \i -> case runParser guard i of
+ (Right _, rest) = (Right acc, rest)
+ (Left _, _) = case runParser p i of
+ (Right r, rest) = runParser (until` p guard [r:acc]) rest
+ (Left e, _) = (Left e, i)
+ try :: (Parser a b) -> Parser a b
+ try p = Parser \i -> case runParser p i of
+ (Left e, _) = (Left e, i)
+ (Right r, rest) = (Right r, rest)
+
+eof :: Parser a Void
+eof = Parser \i -> case i of
+ [] = (Right Void, [])
+ _ = (Left $ Error "", i)
satisfy :: (a -> Bool) -> Parser a a
-satisfy f = one >>= \r -> if (f r) (return r) fail
+satisfy f = top >>= \r -> if (f r) (return r) fail
+
+check :: (a -> Bool) -> Parser a a
+check f = peek >>= \r -> if (f r) (return r) fail
item :: a -> Parser a a | Eq a
item a = satisfy ((==)a)
list :: [a] -> Parser a [a] | Eq a
-list as = mapM item as
\ No newline at end of file
+list as = mapM item as