Add Random.int63

Changes

@@ -12,7 +12,7 @@ Working version
 
 ### Standard library:
 
-- #9487, #9489: Random.int now accepts 62-bit bounds on 64-bit systems.
+- #9487, #9489: Add Random.int63 which allows 62-bit bounds on 64-bit systems.
   (David Allsopp, request by Francois Berenger, review by ??)
 
 ### Other libraries:

stdlib/random.ml

@@ -88,6 +88,11 @@ module State = struct
     let v = r mod n in
     if r - v > 0x3FFFFFFF - n + 1 then intaux s n else v
 
+  let int s bound =
+    if bound > 0x3FFFFFFF || bound <= 0
+    then invalid_arg "Random.int"
+    else intaux s bound
+
   let rec int63aux s n =
     let b1 = bits s in
     let b2 = bits s lsl 30 in
@@ -96,9 +101,9 @@ module State = struct
     let v = r mod n in
     if r - v > max_int - n + 1 then int63aux s n else v
 
-  let int s bound =
+  let int63 s bound =
     if bound <= 0 then
-      invalid_arg "Random.int"
+      invalid_arg "Random.int63"
     else if bound > 0x3FFFFFFF then
       int63aux s bound
     else
@@ -176,6 +181,7 @@ let default = {
 
 let bits () = State.bits default
 let int bound = State.int default bound
+let int63 bound = State.int63 default bound
 let int32 bound = State.int32 default bound
 let nativeint bound = State.nativeint default bound
 let int64 bound = State.int64 default bound

stdlib/random.mli

@@ -39,10 +39,14 @@ val bits : unit -> int
 
 val int : int -> int
 (** [Random.int bound] returns a random integer between 0 (inclusive)
-    and [bound] (exclusive).  [bound] must be greater than 0 and less
-    than {!Stdlib.max_int}
+     and [bound] (exclusive).  [bound] must be greater than 0 and less
+     than 2{^30}. *)
 
-    @before 4.12.0 [bound] had to be less than 2{^30}. *)
+val int63 : int -> int
+(** [Random.int63 bound] is identical to {!int} if [bound] is less than 2{^30},
+    however [bound] may be any positive [int].
+
+    @since 4.12.0 *)
 
 val int32 : Int32.t -> Int32.t
 (** [Random.int32 bound] returns a random integer between 0 (inclusive)
@@ -91,6 +95,7 @@ module State : sig
 
   val bits : t -> int
   val int : t -> int -> int
+  val int63 : t -> int -> int
   val int32 : t -> Int32.t -> Int32.t
   val nativeint : t -> Nativeint.t -> Nativeint.t
   val int64 : t -> Int64.t -> Int64.t