X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=yard.icl;h=612efd188f915f44cacea0e50edc9b791537bebe;hb=f081c2c5e248331eb6e2f090f4afe818fd8259eb;hp=9b2ec23ec1e1a9a9cf8fdd534b0b72be538b2320;hpb=6b3981fb80952fe2c510b6f9b849adb0dff77d2c;p=cc1516.git diff --git a/yard.icl b/yard.icl index 9b2ec23..612efd1 100644 --- a/yard.icl +++ b/yard.icl @@ -21,71 +21,64 @@ instance toString Error where runParser :: (Parser a b) [a] -> (Either Error b, [a]) runParser (Parser f) i = f i - -instance + Error where - (+) r1 r2 = r2 //TODO instance Functor (Parser a) where - fmap f m = liftM f m + fmap f m = liftM f m instance Applicative (Parser a) where - pure a = Parser \i -> (Right a, i) - (<*>) sf p = ap sf p + 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, _) = (Left e, i) + bind p f = Parser \i -> case runParser p i of + (Right r, rest) = runParser (f r) rest + (Left e, _) = (Left e, i) instance Alternative (Parser a) where - 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 $ e1+e2, i) - (Right r, rest) = (Right r, rest) - -//Try the parser, if it fails decorate the error with Expected of the given String and position + 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 $ e1 + e, rest) - (Right r, rest) = (Right r, rest) + (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 $ Error "", []) - [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]) + [] = (Left $ Error "", []) + [x:xs] = (Right x, [x:xs]) -//runs the left parser until the right parser succeeds. Returns the result of the left parser -//Note: if the right parser consumes input then this input is lost! -//If the left parser fails before the right parser succeeds the whole parser fails (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) - + 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) + [] = (Right Void, []) + _ = (Left $ Error "", i) satisfy :: (a -> Bool) -> Parser a a satisfy f = top >>= \r -> if (f r) (return r) fail