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diff --git a/bundles/org.simantics.scl.compiler/tests/org/simantics/scl/compiler/tests/scl/Parsing.scl b/bundles/org.simantics.scl.compiler/tests/org/simantics/scl/compiler/tests/scl/Parsing.scl
new file mode 100644
index 000000000..0ca342a34
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/tests/org/simantics/scl/compiler/tests/scl/Parsing.scl
@@ -0,0 +1,62 @@
+import "Prelude"
+
+"""
+Parser is a function from a string and a position in the
+string to a possible semantics of a substring and the 
+end of the substring.
+"""
+data Parser a = Parser (String -> Integer -> Maybe (a, Integer))
+
+runParser :: Parser a -> String -> Integer -> Maybe (a, Integer)
+runParser (Parser f) = f 
+
+instance Functor Parser where
+    fmap f (Parser p) = Parser (\input pos -> match p input pos with
+        Nothing -> Nothing
+        Just (a, newPos) -> Just (f a, newPos)
+    )
+
+instance Monad Parser where
+    return x = Parser (\_ pos -> Just (x, pos))    
+    (pa >>= f) = Parser (\input pos -> match runParser pa input pos with
+        Nothing -> Nothing
+        Just (a, newPos) -> runParser (f a) input newPos
+    )  
+
+(|||) :: Parser a -> Parser a -> Parser a
+Parser a ||| Parser b = Parser (\input pos -> match a input pos with
+    Nothing -> b input pos
+    Just x -> Just x
+) 
+
+keyword :: String -> Parser ()
+keyword word = Parser (\input pos ->
+    if regionMatches word 0 input pos (length word)
+      then Just ((), pos + (length word))
+      else Nothing
+)
+
+data List a = Nil | Cons a (List a)
+
+listSepL :: Parser () -> Parser a -> Parser (List a)
+listSepL sep el = mdo
+    head <- el
+    tail <- (sep >> listSepL sep el) ||| return Nil
+    return (Cons head tail) 
+
+fromList :: List a -> [a]
+fromList = unfoldr gen
+  where
+    gen Nil        = Nothing
+    gen (Cons h t) = Just (h, t)
+    
+listSep :: Parser () -> Parser a -> Parser [a]    
+listSep sep el = fmap fromList (listSepL sep el) 
+
+aOrB = (keyword "a" >> return "a") ||| (keyword "b" >> return "b")
+
+myParser = listSep (keyword ",") aOrB
+
+main = show (runParser myParser "a,b,b,a" 0)
+--
+Just (["a", "b", "b", "a"], 7)
\ No newline at end of file