Merge pull request #458 from benbellick/add-predicate-combinator

predicate combinators: and_p and or_p

src/core/CCFun.ml

@@ -8,8 +8,11 @@ include Sys
 include Stdlib
 include Fun
 
+let[@inline] and_pred f g x = f x && g x
+let[@inline] or_pred f g x = f x || g x
 let[@inline] compose f g x = g (f x)
 let[@inline] compose_binop f g x y = g (f x) (f y)
+
 let[@inline] curry f x y = f (x, y)
 let[@inline] uncurry f (x, y) = f x y
 

src/core/CCFun.mli

@@ -5,6 +5,16 @@
 include module type of Fun
 (** @inline *)
 
+val and_pred : ('a -> bool) -> ('a -> bool) -> 'a -> bool
+(** [and_p f g x] is [(f x) && (g x)].
+    Produces a predicate which is a conjunction of the two predicates.
+*)
+
+val or_pred : ('a -> bool) -> ('a -> bool) -> 'a -> bool
+(** [or_p f g x] is [(f x) || (g x)].
+    Produces a predicate which is a disjunction of the two predicates.
+*)
+
 val compose : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
 (** [compose f g x] is [g (f x)]. Composition. *)