X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=src%2Fyard.icl;h=9ed60773de8155dd7c3242ac9f12ea24c8e6b66b;hb=3d1c57710eb0b86f13df392f03131157aec22c21;hp=bded7fb94b2c110c8230f7acf8692c8b91a07de2;hpb=4c779c9791b03d96a76956e314cbc95f056448ce;p=cc1516.git

diff --git a/src/yard.icl b/src/yard.icl
index bded7fb..9ed6077 100644
--- a/src/yard.icl
+++ b/src/yard.icl
@@ -12,6 +12,7 @@ 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"
@@ -24,7 +25,7 @@ runParser (Parser f) i = f i
 instance + Error where
     (+) ParseError r = r 
     (+) r ParseError = r
-    (+) _ r          = r
+    (+) r _          = r
  
 instance Functor (Parser a) where
     fmap f m = liftM f m
@@ -36,15 +37,15 @@ 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)
     (<|>) 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
@@ -60,11 +61,42 @@ top = Parser \i -> case i of
     []      = (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])
+
+//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 :: (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)
+
 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