import StdTuple
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 ParseError = "General parse error"
toString (LexError e) = "Lexer error: " +++ e
+ toString (Unexpected e pos) = "Unexpected " +++ e +++ " at position " +++ (toString pos)
runParser :: (Parser a b) [a] -> (Either Error b, [a])
runParser (Parser f) i = f i
+instance + Error where
+ (+) ParseError r = r
+ (+) r ParseError = r
+ (+) r _ = r
+
instance Functor (Parser a) where
fmap f m = liftM f m
empty = Parser \i -> (Left ParseError, i)
(<|>) p1 p2 = Parser \i -> case runParser p1 i of
(Right r, rest) = (Right r, rest)
- (Left _, rest) = runParser p2 i
+ (Left e1, rest) = case runParser p2 i of
+ (Left e2, rest) = (Left $ e1+e2, rest)
+ (Right r, rest) = (Right r, rest)
+
+//Try the parser, if it fails decorate the error with Expected of the given String and position
+(<?>) :: (Parser a b) (String, Int) -> Parser a b
+(<?>) p (e,pos) = Parser \i -> case runParser p i of
+ (Left e1, rest) = (Left $ e1 + Unexpected e pos, rest)
+ (Right r, rest) = (Right r, rest)
fail :: Parser a b
fail = empty
[] = (Left ParseError, [])
[x:xs] = (Right x, xs)
+peek :: Parser a a
+peek = Parser \i -> case i of
+ [] = (Left ParseError, [])
+ [x:xs] = (Right x, [x:xs])
+
+eof :: Parser a Void
+eof = Parser \i -> case i of
+ [] = (Right Void, [])
+ _ = (Left ParseError, i)
+
satisfy :: (a -> Bool) -> Parser a a
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
+list as = mapM item as
\ No newline at end of file