diff options
| -rw-r--r-- | demo/sum.ur | 10 | ||||
| -rw-r--r-- | lib/ur/top.ur | 13 | ||||
| -rw-r--r-- | lib/ur/top.urs | 6 |
3 files changed, 24 insertions, 5 deletions
diff --git a/demo/sum.ur b/demo/sum.ur index 9391637a..566b7899 100644 --- a/demo/sum.ur +++ b/demo/sum.ur @@ -1,10 +1,10 @@ -fun sum (fs ::: {Unit}) (x : $(mapUT int fs)) = +fun sum (fs ::: {Unit}) (fold : folder fs) (x : $(mapUT int fs)) = foldUR [int] [fn _ => int] (fn (nm :: Name) (rest :: {Unit}) [[nm] ~ rest] n acc => n + acc) - 0 [fs] x + 0 [fs] fold x fun main () = return <xml><body> - {[sum {}]}<br/> - {[sum {A = 0, B = 1}]}<br/> - {[sum {C = 2, D = 3, E = 4}]} + {[sum Folder.nil {}]}<br/> + {[sum (Folder.cons [#A] [()] (Folder.cons [#B] [()] Folder.nil)) {A = 0, B = 1}]}<br/> + {[sum (Folder.cons [#D] [()] (Folder.cons [#C] [()] (Folder.cons [#E] [()] Folder.nil))) {C = 2, D = 3, E = 4}]} </body></xml> diff --git a/lib/ur/top.ur b/lib/ur/top.ur index 9016fd27..5d2ae606 100644 --- a/lib/ur/top.ur +++ b/lib/ur/top.ur @@ -6,6 +6,19 @@ con folder = K ==> fn r :: {K} => -> fn [[nm] ~ r] => tf ([nm = v] ++ r)) -> tf [] -> tf r +structure Folder = struct + fun nil K (tf :: {K} -> Type) + (f : nm :: Name -> v :: K -> r :: {K} -> tf r + -> fn [[nm] ~ r] => tf ([nm = v] ++ r)) + (i : tf []) = i + + fun cons K (r ::: {K}) (nm :: Name) (v :: K) [[nm] ~ r] (fold : folder r) + (tf :: {K} -> Type) + (f : nm :: Name -> v :: K -> r :: {K} -> tf r + -> fn [[nm] ~ r] => tf ([nm = v] ++ r)) + (i : tf []) = f [nm] [v] [r] (fold [tf] f i) +end + fun not b = if b then False else True diff --git a/lib/ur/top.urs b/lib/ur/top.urs index d891c80d..d4cd34f4 100644 --- a/lib/ur/top.urs +++ b/lib/ur/top.urs @@ -6,6 +6,12 @@ con folder = K ==> fn r :: {K} => -> fn [[nm] ~ r] => tf ([nm = v] ++ r)) -> tf [] -> tf r +structure Folder : sig + val nil : K --> folder (([]) :: {K}) + val cons : K --> r ::: {K} -> nm :: Name -> v :: K + -> fn [[nm] ~ r] => folder r -> folder ([nm = v] ++ r) +end + val not : bool -> bool |