diff options
Diffstat (limited to 'lib/ur/top.urs')
| -rw-r--r-- | lib/ur/top.urs | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/ur/top.urs b/lib/ur/top.urs index ec098955..a367a989 100644 --- a/lib/ur/top.urs +++ b/lib/ur/top.urs @@ -121,6 +121,15 @@ val foldR3 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type -> tr [] -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> tr r +(* Fold (generalized safe zip) along four heterogenously-typed records *) +val foldR4 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type) -> tf4 :: (K -> Type) + -> tr :: ({K} -> Type) + -> (nm :: Name -> t :: K -> rest :: {K} + -> [[nm] ~ rest] => + tf1 t -> tf2 t -> tf3 t -> tf4 t -> tr rest -> tr ([nm = t] ++ rest)) + -> tr [] + -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> $(map tf4 r) -> tr r + (* Generate some XML by mapping over a uniformly-typed record *) val mapUX : tf :: Type -> ctx :: {Unit} -> (nm :: Name -> rest :: {Unit} -> [[nm] ~ rest] => @@ -159,6 +168,13 @@ val mapX3 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type) -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> xml ctx [] [] +val mapX4 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type) -> tf4 :: (K -> Type) -> ctx :: {Unit} + -> (nm :: Name -> t :: K -> rest :: {K} + -> [[nm] ~ rest] => + tf1 t -> tf2 t -> tf3 t -> tf4 t -> xml ctx [] []) + -> r ::: {K} -> folder r + -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> $(map tf4 r) -> xml ctx [] [] + (* Note that the next two functions return elements in the _reverse_ of the natural order! * Such a choice interacts well with the time complexity of standard list operations. * It's easy to regain the natural order by inverting a query's 'ORDER BY' condition. *) |