diff options
Diffstat (limited to 'src/Data')
-rw-r--r-- | src/Data/Array/Mixed.hs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/Data/Array/Mixed.hs b/src/Data/Array/Mixed.hs index 24a8482..1a622fb 100644 --- a/src/Data/Array/Mixed.hs +++ b/src/Data/Array/Mixed.hs @@ -7,6 +7,7 @@ {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE LambdaCase #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE PatternSynonyms #-} {-# LANGUAGE QuantifiedConstraints #-} @@ -720,6 +721,12 @@ snatLengthHList :: HList f list -> SNat (Rank list) snatLengthHList HNil = SNat snatLengthHList (_ `HCons` l) | SNat <- snatLengthHList l = SNat +permFromList :: [Int] -> (forall list. HList SNat list -> r) -> r +permFromList [] k = k HNil +permFromList (x : xs) k = withSomeSNat (fromIntegral x) $ \case + Just sn -> permFromList xs $ \list -> k (sn `HCons` list) + Nothing -> error $ "Data.Array.Mixed.permFromList: negative number in list: " ++ show x + type family TakeLen ref l where TakeLen '[] l = '[] TakeLen (_ : ref) (x : xs) = x : TakeLen ref xs |