Finish assignment 10

1 files changed, 11 insertions, 3 deletions

diff --git a/assignment-10/sets.icl b/assignment-10/sets.icl
index 2a19584..de4a62a 100644
--- a/assignment-10/sets.icl
+++ b/assignment-10/sets.icl
@@ -77,6 +77,9 @@ for  :== For bimapId
 :: Logical :== Expression Bool
 :: Ident :== String
 
+fail :: (String -> StateT s (MaybeError String) a)
+fail = StateT o const o Error
+
 store :: Ident v -> StateT SetState m v | Monad m & TC v
 store i v = modify ('M'.put i (dynamic v)) $> v
 
@@ -86,9 +89,6 @@ read i = gets ('M'.get i) >>= \v -> case v of
 	Just d         -> fail $ "type error, " <+ typeCodeOfDynamic d <+ " for '" <+ i <+ "'"
 	Nothing        -> fail $ "unknown variable '" <+ i <+ "'"
 
-fail :: String -> StateT s (MaybeError String) a
-fail e = StateT \_ -> Error e
-
 eval :: (Expression a) -> Sem a | TC a
 eval (New bm xs)            = pure $ bm.map_from xs
 eval (Elem bm x)            = pure $ bm.map_from x
@@ -113,6 +113,14 @@ eval (If b t e)             = eval b >>= \b -> eval $ if b t e
 eval (For bm id s e)        = bm.map_from <$> (eval s >>= mapM (\x -> store id x >>| eval e))
 eval (s :. t)               = eval s >>| eval t
 
+/**
+ * I did not manage to get the iTasks simulator working, because the compiler
+ * 'cannot build a generic representation of an existential type'.
+ * I'm sure it would be *possible* by implementing an Editor manually, forcing
+ * all Bimaps to bimapId and using cast :: a -> b in case of type errors, but
+ * did not try to do this due to time constraints.
+ */
+
 Start = evalStateT (eval stmt) 'M'.newMap
 where
 	stmt :: Expression [Int]