blob: cb422b60d7c5c23a9fdd6ec70aef23648690aa38 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
|
diff --git a/templates/wrappers.hs b/templates/wrappers.hs
index a1a1a6d..c020cc7 100644
--- a/templates/wrappers.hs
+++ b/templates/wrappers.hs
@@ -284,6 +284,19 @@ runAlex input (Alex f)
newtype Alex a = Alex { unAlex :: AlexState -> Either String (AlexState, a) }
+instance Functor Alex where
+ fmap f a = Alex $ \s -> case unAlex a s of
+ Left msg -> Left msg
+ Right (s', a') -> Right (s', f a')
+
+instance Applicative Alex where
+ pure a = Alex $ \s -> Right (s, a)
+ fa <*> a = Alex $ \s -> case unAlex fa s of
+ Left msg -> Left msg
+ Right (s', f) -> case unAlex a s' of
+ Left msg -> Left msg
+ Right (s'', b) -> Right (s'', f b)
+
instance Monad Alex where
m >>= k = Alex $ \s -> case unAlex m s of
Left msg -> Left msg
|
GitWeb
