From 8d41623ba50d20b64b7e1e0e8509cf0e0133fe27 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Sat, 26 Mar 2016 12:05:31 +0100
Subject: [PATCH] add `{CCArray,CCVector,CCList}.(--^)` for right-open ranges

---
 src/core/CCArray.ml   | 22 ++++++++++++++++++++++
 src/core/CCArray.mli  |  4 ++++
 src/core/CCList.ml    |  8 ++++++++
 src/core/CCList.mli   |  7 +++++++
 src/core/CCVector.ml  | 16 ++++++++++++++++
 src/core/CCVector.mli |  5 +++++
 6 files changed, 62 insertions(+)

diff --git a/src/core/CCArray.ml b/src/core/CCArray.ml
index de3b8b43..848952a6 100644
--- a/src/core/CCArray.ml
+++ b/src/core/CCArray.ml
@@ -443,6 +443,28 @@ let (--) i j =
   else
     Array.init (i-j+1) (fun k -> i-k)
 
+(*$T
+  (1 -- 4) |> Array.to_list = [1;2;3;4]
+  (4 -- 1) |> Array.to_list = [4;3;2;1]
+  (0 -- 0) |> Array.to_list = [0]
+*)
+
+(*$Q
+  Q.(pair small_int small_int) (fun (a,b) -> \
+    (a -- b) |> Array.to_list = CCList.(a -- b))
+*)
+
+let (--^) i j =
+  if i=j then [| |]
+  else if i>j
+    then Array.init (i-j) (fun k -> i-k)
+    else Array.init (j-i) (fun k -> i+k)
+
+(*$Q
+  Q.(pair small_int small_int) (fun (a,b) -> \
+    (a --^ b) |> Array.to_list = CCList.(a --^ b))
+*)
+
 (** all the elements of a, but the i-th, into a list *)
 let except_idx a i =
   foldi
diff --git a/src/core/CCArray.mli b/src/core/CCArray.mli
index dd87dd40..71853a1e 100644
--- a/src/core/CCArray.mli
+++ b/src/core/CCArray.mli
@@ -166,6 +166,10 @@ val except_idx : 'a t -> int -> 'a list
 val (--) : int -> int -> int t
 (** Range array *)
 
+val (--^) : int -> int -> int t
+(** Range array, excluding right bound
+    @since NEXT_RELEASE *)
+
 val random : 'a random_gen -> 'a t random_gen
 val random_non_empty : 'a random_gen -> 'a t random_gen
 val random_len : int -> 'a random_gen -> 'a t random_gen
diff --git a/src/core/CCList.ml b/src/core/CCList.ml
index 5d926df0..09a7d067 100644
--- a/src/core/CCList.ml
+++ b/src/core/CCList.ml
@@ -763,11 +763,18 @@ let range' i j =
 
 let (--) = range
 
+let (--^) = range'
+
 (*$T
   append (range 0 100) (range 101 1000) = range 0 1000
   append (range 1000 501) (range 500 0) = range 1000 0
 *)
 
+(*$Q
+  Q.(pair small_int small_int) (fun (a,b) -> \
+    let l = (a--^b) in not (List.mem b l))
+*)
+
 let replicate i x =
   let rec aux acc i =
     if i = 0 then acc
@@ -1103,6 +1110,7 @@ module Infix = struct
   let (<$>) = (<$>)
   let (>>=) = (>>=)
   let (--) = (--)
+  let (--^) = (--^)
 end
 
 (** {2 IO} *)
diff --git a/src/core/CCList.mli b/src/core/CCList.mli
index 8a9afb25..5da90920 100644
--- a/src/core/CCList.mli
+++ b/src/core/CCList.mli
@@ -263,6 +263,10 @@ val range' : int -> int -> int t
 val (--) : int -> int -> int t
 (** Infix alias for [range] *)
 
+val (--^) : int -> int -> int t
+(** Infix alias for [range']
+    @since NEXT_RELEASE *)
+
 val replicate : int -> 'a -> 'a t
 (** Replicate the given element [n] times *)
 
@@ -482,6 +486,9 @@ module Infix : sig
   val (<$>) : ('a -> 'b) -> 'a t -> 'b t
   val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
   val (--) : int -> int -> int t
+
+  val (--^) : int -> int -> int t
+  (** @since NEXT_RELEASE *)
 end
 
 (** {2 IO} *)
diff --git a/src/core/CCVector.ml b/src/core/CCVector.ml
index 6eb571e0..0fce2699 100644
--- a/src/core/CCVector.ml
+++ b/src/core/CCVector.ml
@@ -631,12 +631,28 @@ let (--) i j =
     then init (i-j+1) (fun k -> i-k)
     else init (j-i+1) (fun k -> i+k)
 
+(*$Q
+  Q.(pair small_int small_int) (fun (a,b) -> \
+    (a -- b) |> to_list = CCList.(a -- b))
+*)
+
+let (--^) i j =
+  if i=j then create()
+  else if i>j
+    then init (i-j) (fun k -> i-k)
+    else init (j-i) (fun k -> i+k)
+
 (*$T
   (1 -- 4) |> to_list = [1;2;3;4]
   (4 -- 1) |> to_list = [4;3;2;1]
   (0 -- 0) |> to_list = [0]
 *)
 
+(*$Q
+  Q.(pair small_int small_int) (fun (a,b) -> \
+    (a --^ b) |> to_list = CCList.(a --^ b))
+*)
+
 let of_array a =
   if Array.length a = 0
   then create ()
diff --git a/src/core/CCVector.mli b/src/core/CCVector.mli
index ea9088d9..10b5c17d 100644
--- a/src/core/CCVector.mli
+++ b/src/core/CCVector.mli
@@ -237,6 +237,11 @@ val (--) : int -> int -> (int, 'mut) t
     therefore the result is never empty).
     Example: [1 -- 10] returns the vector [[1;2;3;4;5;6;7;8;9;10]] *)
 
+val (--^) : int -> int -> (int, 'mut) t
+(** Range of integers, either ascending or descending, but excluding right.,
+    Example: [1 --^ 10] returns the vector [[1;2;3;4;5;6;7;8;9]]
+    @since NEXT_RELEASE *)
+
 val of_array : 'a array -> ('a, 'mut) t
 val of_list : 'a list -> ('a, 'mut) t
 val to_array : ('a,_) t -> 'a array