X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=src%2Fyard.icl;h=9b2ec23ec1e1a9a9cf8fdd534b0b72be538b2320;hb=f5231ebadae1ac54e25dbf5819debb3ab625826d;hp=582ea1d6a25e5a8eb2980456c3166622e22263de;hpb=3275e6545ebf0901e962065416cf95f5b35fa828;p=cc1516.git diff --git a/src/yard.icl b/src/yard.icl index 582ea1d..9b2ec23 100644 --- a/src/yard.icl +++ b/src/yard.icl @@ -15,17 +15,15 @@ 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) + 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 + Error where - (+) ParseError r = r - (+) r ParseError = r - (+) r _ = r + (+) r1 r2 = r2 //TODO instance Functor (Parser a) where fmap f m = liftM f m @@ -37,20 +35,20 @@ instance Applicative (Parser a) where 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) + (Left e, _) = (Left e, i) instance Alternative (Parser a) where - empty = Parser \i -> (Left ParseError, 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 $ e1+e2, rest) - (Right r, rest) = (Right r, rest) + (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 -() :: (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) +() :: (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) fail :: Parser a b @@ -58,18 +56,36 @@ fail = empty top :: Parser a a top = Parser \i -> case i of - [] = (Left ParseError, []) + [] = (Left $ Error "", []) [x:xs] = (Right x, xs) peek :: Parser a a peek = Parser \i -> case i of - [] = (Left ParseError, []) + [] = (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) + + eof :: Parser a Void eof = Parser \i -> case i of [] = (Right Void, []) - _ = (Left ParseError, i) + _ = (Left $ Error "", i) satisfy :: (a -> Bool) -> Parser a a satisfy f = top >>= \r -> if (f r) (return r) fail @@ -81,4 +97,4 @@ 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