Mercurial > urweb
changeset 1480:aa0c6382aa57
top.urs: More comments
author | Robin Green <greenrd@greenrd.org> |
---|---|
date | Tue, 28 Jun 2011 11:55:57 +0100 (2011-06-28) |
parents | f561025bb68e |
children | 3061d1bf4b2d |
files | lib/ur/top.urs |
diffstat | 1 files changed, 31 insertions(+), 0 deletions(-) [+] |
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--- a/lib/ur/top.urs Sun Jun 26 19:45:21 2011 -0400 +++ b/lib/ur/top.urs Tue Jun 28 11:55:57 2011 +0100 @@ -21,21 +21,34 @@ val not : bool -> bool +(* Type-level identity function *) con id = K ==> fn t :: K => t + +(* Type-level function which yields the value-level record + described by the given type-level record *) con record = fn t :: {Type} => $t + con fst = K1 ==> K2 ==> fn t :: (K1 * K2) => t.1 con snd = K1 ==> K2 ==> fn t :: (K1 * K2) => t.2 con fst3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.1 con snd3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.2 con thd3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.3 +(* Convert a record of n Units into a type-level record where + each field has the same value (which describes a uniformly + typed record) *) con mapU = K ==> fn f :: K => map (fn _ :: Unit => f) +(* Existential type former *) con ex :: K --> (K -> Type) -> Type +(* Introduction of existential type *) val ex_intro : K --> tf :: (K -> Type) -> choice :: K -> tf choice -> ex tf + +(* Eliminator for existential type *) val ex_elim : K --> tf ::: (K -> Type) -> ex tf -> res ::: Type -> (choice :: K -> tf choice -> res) -> res +(* Composition of ordinary (value-level) functions *) val compose : t1 ::: Type -> t2 ::: Type -> t3 ::: Type -> (t2 -> t3) -> (t1 -> t2) -> (t1 -> t3) @@ -45,37 +58,52 @@ val txt : t ::: Type -> ctx ::: {Unit} -> use ::: {Type} -> show t -> t -> xml ctx use [] +(* Given a polymorphic type (tf) and a means of constructing + "default" values of tf applied to arbitrary arguments, + constructs records consisting of those "default" values *) val map0 : K --> tf :: (K -> Type) -> (t :: K -> tf t) -> r ::: {K} -> folder r -> $(map tf r) + +(* Given two polymorphic types (tf1 and tf2) and a means of + converting from tf1 t to tf2 t for arbitrary t, + converts records of tf1's to records of tf2's *) val mp : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> (t ::: K -> tf1 t -> tf2 t) -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) + +(* Two-argument conversion form of mp *) val map2 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf :: (K -> Type) -> (t ::: K -> tf1 t -> tf2 t -> tf t) -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf r) + +(* Three-argument conversion form of mp *) val map3 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type) -> tf :: (K -> Type) -> (t ::: K -> tf1 t -> tf2 t -> tf3 t -> tf t) -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> $(map tf r) +(* Fold along a uniformly (homogenously) typed record *) val foldUR : tf :: Type -> tr :: ({Unit} -> Type) -> (nm :: Name -> rest :: {Unit} -> [[nm] ~ rest] => tf -> tr rest -> tr ([nm] ++ rest)) -> tr [] -> r ::: {Unit} -> folder r -> $(mapU tf r) -> tr r +(* Fold (generalized safe zip) along two equal-length uniformly-typed records *) val foldUR2 : tf1 :: Type -> tf2 :: Type -> tr :: ({Unit} -> Type) -> (nm :: Name -> rest :: {Unit} -> [[nm] ~ rest] => tf1 -> tf2 -> tr rest -> tr ([nm] ++ rest)) -> tr [] -> r ::: {Unit} -> folder r -> $(mapU tf1 r) -> $(mapU tf2 r) -> tr r +(* Fold along a heterogenously-typed record *) val foldR : K --> tf :: (K -> Type) -> tr :: ({K} -> Type) -> (nm :: Name -> t :: K -> rest :: {K} -> [[nm] ~ rest] => tf t -> tr rest -> tr ([nm = t] ++ rest)) -> tr [] -> r ::: {K} -> folder r -> $(map tf r) -> tr r +(* Fold (generalized safe zip) along two heterogenously-typed records *) val foldR2 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tr :: ({K} -> Type) -> (nm :: Name -> t :: K -> rest :: {K} @@ -84,6 +112,7 @@ -> tr [] -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> tr r +(* Fold (generalized safe zip) along three heterogenously-typed records *) val foldR3 : K --> tf1 :: (K -> Type) -> tf2 :: (K -> Type) -> tf3 :: (K -> Type) -> tr :: ({K} -> Type) -> (nm :: Name -> t :: K -> rest :: {K} @@ -92,11 +121,13 @@ -> tr [] -> r ::: {K} -> folder r -> $(map tf1 r) -> $(map tf2 r) -> $(map tf3 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] => tf -> xml ctx [] []) -> r ::: {Unit} -> folder r -> $(mapU tf r) -> xml ctx [] [] +(* Generate some XML by mapping over a heterogenously-typed record *) val mapX : K --> tf :: (K -> Type) -> ctx :: {Unit} -> (nm :: Name -> t :: K -> rest :: {K} -> [[nm] ~ rest] =>