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authorGravatar Adam Chlipala <adam@chlipala.net>2019-02-09 14:01:26 -0500
committerGravatar Adam Chlipala <adam@chlipala.net>2019-02-09 14:01:26 -0500
commit0aab3f48920058051d61215f23440d1042659c92 (patch)
tree2a5934cb385af5410191acc38ddefc611f169d31
parent68cf048ec0c581c5debd293363ed0037bb07a920 (diff)
Top: foldR4 and mapX4
-rw-r--r--lib/ur/top.ur21
-rw-r--r--lib/ur/top.urs16
2 files changed, 37 insertions, 0 deletions
diff --git a/lib/ur/top.ur b/lib/ur/top.ur
index 02567917..92f1ecdd 100644
--- a/lib/ur/top.ur
+++ b/lib/ur/top.ur
@@ -172,6 +172,17 @@ fun foldR3 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [tr :: {
f [nm] [t] [rest] r1.nm r2.nm r3.nm (acc (r1 -- nm) (r2 -- nm) (r3 -- nm)))
(fn _ _ _ => i)
+fun foldR4 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [tf4 :: K -> Type] [tr :: {K} -> Type]
+ (f : nm :: Name -> t :: K -> rest :: {K}
+ -> [[nm] ~ rest] =>
+ tf1 t -> tf2 t -> tf3 t -> tf4 t -> tr rest -> tr ([nm = t] ++ rest))
+ (i : tr []) [r ::: {K}] (fl : folder r) =
+ fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> $(map tf4 r) -> tr r]
+ (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest]
+ (acc : _ -> _ -> _ -> _ -> tr rest) r1 r2 r3 r4 =>
+ f [nm] [t] [rest] r1.nm r2.nm r3.nm r4.nm (acc (r1 -- nm) (r2 -- nm) (r3 -- nm) (r4 -- nm)))
+ (fn _ _ _ _ => i)
+
fun mapUX [tf :: Type] [ctx :: {Unit}]
(f : nm :: Name -> rest :: {Unit} -> [[nm] ~ rest] => tf -> xml ctx [] []) =
@@foldR [fn _ => tf] [fn _ => xml ctx [] []]
@@ -224,6 +235,16 @@ fun mapX3 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [ctx :: {
<xml>{f [nm] [t] [rest] r1 r2 r3}{acc}</xml>)
<xml/>
+fun mapX4 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [tf4 :: K -> Type] [ctx :: {Unit}]
+ (f : nm :: Name -> t :: K -> rest :: {K}
+ -> [[nm] ~ rest] =>
+ tf1 t -> tf2 t -> tf3 t -> tf4 t -> xml ctx [] []) =
+ @@foldR4 [tf1] [tf2] [tf3] [tf4] [fn _ => xml ctx [] []]
+ (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest]
+ r1 r2 r3 r4 acc =>
+ <xml>{f [nm] [t] [rest] r1 r2 r3 r4}{acc}</xml>)
+ <xml/>
+
fun query1 [t ::: Name] [fs ::: {Type}] [state ::: Type] (q : sql_query [] [] [t = fs] [])
(f : $fs -> state -> transaction state) (i : state) =
query q (fn r => f r.t) i
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. *)