diff options
Diffstat (limited to 'lib/util.ml')
-rw-r--r-- | lib/util.ml | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/lib/util.ml b/lib/util.ml index 0f79c10df..cae996e33 100644 --- a/lib/util.ml +++ b/lib/util.ml @@ -132,9 +132,36 @@ type ('a, 'b) union = ('a, 'b) CSig.union = Inl of 'a | Inr of 'b type 'a until = 'a CSig.until = Stop of 'a | Cont of 'a type ('a, 'b) eq = ('a, 'b) CSig.eq = Refl : ('a, 'a) eq -let map_union f g = function - | Inl a -> Inl (f a) - | Inr b -> Inr (g b) +module Union = +struct + let map f g = function + | Inl a -> Inl (f a) + | Inr b -> Inr (g b) + + (** Lifting equality onto union types. *) + let equal f g x y = match x, y with + | Inl x, Inl y -> f x y + | Inr x, Inr y -> g x y + | _, _ -> false + + let fold_left f g a = function + | Inl y -> f a y + | Inr y -> g a y + | _ -> a +end + +let map_union = Union.map + +(** Lifting equality onto union types. *) +let equal_union f g x y = match x, y with + | Inl x, Inl y -> f x y + | Inr x, Inr y -> g x y + | _, _ -> false + +let fold_left_union f g a = function + | Inl y -> f a y + | Inr y -> g a y + | _ -> a type iexn = Exninfo.iexn |