CCFormat(fix): restaure the behaviour of CCFormat.opt

This reverts commit b649ac9dc5.

.github/workflows/format.yml

@@ -0,0 +1,28 @@
+name: format
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  format:
+    name: format
+    strategy:
+      matrix:
+        ocaml-compiler:
+            - '5.3'
+    runs-on: 'ubuntu-latest'
+    steps:
+      - uses: actions/checkout@main
+      - name: Use OCaml ${{ matrix.ocaml-compiler }}
+        uses: ocaml/setup-ocaml@v3
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-compiler }}
+          dune-cache: true
+          allow-prerelease-opam: true
+
+      - run: opam install ocamlformat.0.27.0
+      - run: opam exec -- make format-check
+

.github/workflows/gh-pages.yml

@@ -13,9 +13,9 @@ jobs:
       - uses: actions/checkout@main
 
       - name: Use OCaml
-        uses: ocaml/setup-ocaml@v2
+        uses: ocaml/setup-ocaml@v3
         with:
-          ocaml-compiler: '4.14'
+          ocaml-compiler: '5.2'
           dune-cache: false
 
       - name: Deps

.github/workflows/main.yml

@@ -19,14 +19,14 @@ jobs:
             - '4.08'
             - '4.10'
             - '4.14'
-            - '5.2'
+            - '5.3'
             - 'ocaml-variants.5.0.0+options,ocaml-option-bytecode-only'
 
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@main
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
-        uses: ocaml/setup-ocaml@v2
+        uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: ${{ matrix.ocaml-compiler }}
           dune-cache: true
@@ -52,7 +52,7 @@ jobs:
     steps:
       - uses: actions/checkout@main
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
-        uses: ocaml/setup-ocaml@v2
+        uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: ${{ matrix.ocaml-compiler }}
           dune-cache: true
@@ -62,23 +62,3 @@ jobs:
           opam install containers-data --deps-only  # no test deps
       - run: opam exec -- dune build '@install'
       - run: opam exec -- dune runtest -j 1 -p containers --profile=release # test only core on non-ubuntu platform
-
-  format:
-    name: format
-    strategy:
-      matrix:
-        ocaml-compiler:
-            - '5.2'
-    runs-on: 'ubuntu-latest'
-    steps:
-      - uses: actions/checkout@main
-      - name: Use OCaml ${{ matrix.ocaml-compiler }}
-        uses: ocaml/setup-ocaml@v2
-        with:
-          ocaml-compiler: ${{ matrix.ocaml-compiler }}
-          dune-cache: true
-          allow-prerelease-opam: true
-
-      - run: opam install ocamlformat.0.26.2
-      - run: opam exec -- make format-check
-

.ocamlformat

@@ -1,4 +1,4 @@
-version = 0.26.2
+version = 0.27.0
 profile=conventional
 margin=80
 if-then-else=k-r
@@ -12,3 +12,4 @@ field-space=tight-decl
 leading-nested-match-parens=true
 module-item-spacing=compact
 quiet=true
+parse-docstrings=false

CHANGELOG.md

@@ -1,11 +1,34 @@
-# Changelog
 
 ## main
 - breaking: CCListLabel.compare and CCListLabel.equal takes the function on the elements as named arguments
 - breaking: CCListLabel.init now takes the length as a named arguments to follow the Stdlib
-- breaking: invert the argument of CCFun.compose to align it with the Stdlib
 - breaking: change the semantic of CCFloat.{min,max} with respect to NaN to follow the Stdlib
 - breaking: change the semantic of CCInt.rem with respect to negative number to follow the Stdlib
+- breaking: change the order of argument of CCMap.add_seq to align with the stdlib.
+
+## 3.17
+
+- feat: add `CCAtomic.update_cas`
+- feat: add `Pvec.flat_map`
+- faster `List.take_drop` thanks to a trick by nojb
+
+- move to ocamlformat 0.27, format code
+- test: enrich pvec test
+- Patch CBor roundtrip property to hold for nan's too (thanks @jmid)
+
+## 3.16
+
+
+- breaking: Renamed predicate parameter of `take_while`, `rtake_while` from `p` to `f`, aligining it with pre-existing `drop_while`.
+
+- feat: add `containers.leb128` library
+- feat: add `CCFun.with_return`
+- Added functions to the `Char` module to check common character properties.
+- feat: add `CCVector.findi`
+
+
+- fix: compat with OCaml 5.4
+- fix: oob(!!) in CCHash.bytes
 
 ## 3.15
 

benchs/ref_impl.ml

@@ -128,8 +128,9 @@ module PersistentHashtbl (H : Hashtbl.HashedType) = struct
       t := Add (k, v', t');
       Table.remove tbl k;
       t'
-    with Not_found -> (* not member, nothing to do *)
-                      t
+    with Not_found ->
+      (* not member, nothing to do *)
+      t
 
   (*$R
     let h = H.of_seq my_seq in

benchs/run_benchs.ml

@@ -97,6 +97,14 @@ module L = struct
     else
       Sek.Persistent.of_list 0 [ x; x + 1; x + 2; x + 3 ]
 
+  let f_pvec x =
+    if x mod 10 = 0 then
+      Pvec.empty
+    else if x mod 5 = 1 then
+      Pvec.of_list [ x; x + 1 ]
+    else
+      Pvec.of_list [ x; x + 1; x + 2; x + 3 ]
+
   let flat_map_kont f l =
     let rec aux f l kont =
       match l with
@@ -118,6 +126,7 @@ module L = struct
     let l = CCList.(1 -- n) in
     let ral = CCRAL.of_list l in
     let sek = Sek.Persistent.of_list 0 l in
+    let pvec = Pvec.of_list l in
     let flatten_map_ l () =
       ignore @@ Sys.opaque_identity @@ List.flatten (CCList.map f_ l)
     and flatmap_kont l () = ignore @@ Sys.opaque_identity @@ flat_map_kont f_ l
@@ -128,6 +137,8 @@ module L = struct
       ignore @@ Sys.opaque_identity @@ CCRAL.flat_map f_ral_ l
     and flatmap_sek s () =
       ignore @@ Sys.opaque_identity @@ Sek.Persistent.flatten_map 0 f_sek_ s
+    and flat_map_pvec v () =
+      ignore @@ Sys.opaque_identity @@ Pvec.flat_map f_pvec v
     in
     B.throughputN time ~repeat
       [
@@ -137,6 +148,7 @@ module L = struct
         "flatten o map", flatten_map_ l, ();
         "ral_flatmap", flatmap_ral_ ral, ();
         "sek_flatmap", flatmap_sek sek, ();
+        "pvec.flatmap", flat_map_pvec pvec, ();
       ]
 
   (* APPEND *)
@@ -180,6 +192,33 @@ module L = struct
 
   (* FLATTEN *)
 
+  (*
+  let[@tail_mod_cons] rec append_to_flattened first_list tail =
+    match first_list, tail with
+    | _, [] -> first_list
+    | x1 :: x2 :: x3 :: x4 :: first_list', _ ->
+      x1 :: x2 :: x3 :: x4 :: append_to_flattened first_list' tail
+    | [ x1; x2; x3 ], _ -> x1 :: x2 :: x3 :: append_to_flattened [] tail
+    | [ x1; x2 ], _ -> x1 :: x2 :: append_to_flattened [] tail
+    | [ x ], first_list' :: tail' -> x :: append_to_flattened first_list' tail'
+    | [], first_list' :: tail' -> append_to_flattened first_list' tail'
+
+  let flatten_trmc l = append_to_flattened [] l
+  *)
+
+  let[@tail_mod_cons] rec flatten_trmc = function
+    | [] -> []
+    | l1 :: tl -> append_to_flattened l1 tl
+
+  and[@tail_mod_cons] append_to_flattened first_list tail =
+    match first_list with
+    | [] -> flatten_trmc tail
+    | x1 :: [] -> x1 :: flatten_trmc tail
+    | [ x1; x2 ] -> x1 :: x2 :: flatten_trmc tail
+    | [ x1; x2; x3 ] -> x1 :: x2 :: x3 :: flatten_trmc tail
+    | x1 :: x2 :: x3 :: x4 :: first_list' ->
+      x1 :: x2 :: x3 :: x4 :: append_to_flattened first_list' tail
+
   let bench_flatten ?(time = 2) n =
     let fold_right_append_ l () =
       opaque_ignore (List.fold_right List.append l [] : _ list)
@@ -195,7 +234,7 @@ module L = struct
       opaque_ignore (Pvec.fold_left Pvec.append Pvec.empty v : _ Pvec.t)
     in
     let l =
-      CCList.mapi (fun i x -> CCList.(x -- (x + min i 100))) CCList.(1 -- n)
+      CCList.mapi (fun i x -> CCList.(x -- (x + (i mod 100)))) CCList.(1 -- n)
     in
     let sek =
       Sek.Persistent.of_list (Sek.Persistent.create 0)
@@ -208,6 +247,8 @@ module L = struct
       [
         "CCList.flatten", (fun () -> ignore (CCList.flatten l)), ();
         "List.flatten", (fun () -> ignore (List.flatten l)), ();
+        "List.flatten_trmc", (fun () -> ignore (flatten_trmc l)), ();
+        "List.concat_map id", (fun () -> ignore (List.concat_map Fun.id l)), ();
         "fold_right append", fold_right_append_ l, ();
         "funvec.(fold append)", funvec_flatten v, ();
         "pvec.(fold append)", pvec_flatten pv, ();
@@ -284,7 +325,7 @@ module L = struct
       for i = 0 to n - 1 do
         opaque_ignore (CCRAL.set l i (-i))
       done
-      (* TODO: implement set
+    (* TODO: implement set
          and bench_funvec l () =
            for _i = 0 to n-1 do opaque_ignore (CCFun_vec.set (* TODO *)) done
       *)
@@ -447,7 +488,7 @@ module L = struct
                    [
                      app_int (bench_flatten ~time:2) 100;
                      app_int (bench_flatten ~time:2) 10_000;
-                     app_int (bench_flatten ~time:4) 100_000;
+                     app_int (bench_flatten ~time:2) 100_000;
                    ];
              "append"
              @>> B.Tree.concat
@@ -810,8 +851,8 @@ module Tbl = struct
     end in
     (module T)
 
-  let persistent_hashtbl_ref :
-      type a. a key_type -> (module MUT with type key = a) =
+  let persistent_hashtbl_ref : type a.
+      a key_type -> (module MUT with type key = a) =
    fun key ->
     let (module Key), name = arg_make key in
     let module T = Ref_impl.PersistentHashtbl (Key) in

containers-data.opam

@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "3.15"
+version: "3.17"
 synopsis: "A set of advanced datatypes for containers"
 maintainer: ["c-cube"]
 authors: ["c-cube"]

containers.opam

@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "3.15"
+version: "3.17"
 synopsis:
   "A modular, clean and powerful extension of the OCaml standard library"
 maintainer: ["c-cube"]

dune-project

@@ -1,42 +1,60 @@
 (lang dune 3.0)
+
 (name containers)
+
 (generate_opam_files true)
 
-(version 3.15)
+(version 3.17)
+
 (authors c-cube)
+
 (maintainers c-cube)
+
 (license BSD-2-Clause)
+
 (homepage "https://github.com/c-cube/ocaml-containers/")
-(source (github c-cube/ocaml-containers))
+
+(source
+ (github c-cube/ocaml-containers))
 
 (package
-  (name containers)
-  (synopsis "A modular, clean and powerful extension of the OCaml standard library")
-  (tags (stdlib containers iterators list heap queue))
-  (depends
-    (ocaml (>= 4.08))
-    either
-    dune-configurator
-    (qcheck-core (and (>= 0.18) :with-test))
-    (yojson :with-test)
-    (iter :with-test)
-    (gen :with-test)
-    (csexp :with-test)
-    (uutf :with-test)
-    (odoc :with-doc))
-  (depopts
-    base-unix
-    base-threads))
+ (name containers)
+ (synopsis
+  "A modular, clean and powerful extension of the OCaml standard library")
+ (tags
+  (stdlib containers iterators list heap queue))
+ (depends
+  (ocaml
+   (>= 4.08))
+  either
+  dune-configurator
+  (qcheck-core
+   (and
+    (>= 0.18)
+    :with-test))
+  (yojson :with-test)
+  (iter :with-test)
+  (gen :with-test)
+  (csexp :with-test)
+  (uutf :with-test)
+  (odoc :with-doc))
+ (depopts base-unix base-threads))
 
 (package
-  (name containers-data)
-  (synopsis "A set of advanced datatypes for containers")
-  (tags (containers RAL function vector okasaki))
-  (depends
-    (ocaml (>= 4.08))
-    (containers (= :version))
-    (qcheck-core (and (>= 0.18) :with-test))
-    (iter :with-test)
-    (gen :with-test)
-    (mdx :with-test)
-    (odoc :with-doc)))
+ (name containers-data)
+ (synopsis "A set of advanced datatypes for containers")
+ (tags
+  (containers RAL function vector okasaki))
+ (depends
+  (ocaml
+   (>= 4.08))
+  (containers
+   (= :version))
+  (qcheck-core
+   (and
+    (>= 0.18)
+    :with-test))
+  (iter :with-test)
+  (gen :with-test)
+  (mdx :with-test)
+  (odoc :with-doc)))

src/codegen/containers_codegen.ml

@@ -108,7 +108,8 @@ module Bitfield = struct
     if self.emit_failure_if_too_wide then
       fpf out
         "(* check that int size is big enough *)@,\
-         @[let () = assert (Sys.int_size >= %d);;@]" (total_width self);
+         @[let () = assert (Sys.int_size >= %d);;@]"
+        (total_width self);
     fpf out "@]"
 
   let gen_mli self : code =

src/core/CCArray.ml

@@ -93,7 +93,7 @@ let sort_indices cmp a =
   Array.sort (fun k1 k2 -> cmp a.(k1) a.(k2)) b;
   b
 
-let sort_ranking cmp a = sort_indices compare (sort_indices cmp a)
+let sort_ranking cmp a = sort_indices CCInt.compare (sort_indices cmp a)
 
 let rev a =
   let b = Array.copy a in

src/core/CCAtomic.ml

@@ -46,3 +46,24 @@ let[@inline never] decr r =
 (* atomic *)
 
 [@@@endif]
+
+(** Update loop with a compare-and-swap, and some basic backoff behavior.
+    [update_cas atomic f] is, in essence,
+    [let res, x = f !atomic in atomic := x; res]
+    done atomically. [f] might be called multiple times and must be as cheap
+    as possible.
+    @since 3.17 *)
+let update_cas (type res) (self : 'a t) (f : 'a -> res * 'a) : res =
+  let exception Ret of res in
+  let backoff = ref 1 in
+  try
+    while true do
+      let old_val = get self in
+      let res, new_val = f old_val in
+      if compare_and_set self old_val new_val then raise_notrace (Ret res);
+
+      Containers_domain.relax_loop !backoff;
+      backoff := min 128 (2 * !backoff)
+    done;
+    assert false
+  with Ret r -> r

src/core/CCChar.ml

@@ -23,3 +23,12 @@ module Infix = struct
 end
 
 include Infix
+
+let is_uppercase_ascii c = c > '\064' && c < '\091'
+let is_lowercase_ascii c = c > '\096' && c < '\123'
+
+let is_letter_ascii c =
+  (is_lowercase_ascii [@inlined]) c || (is_uppercase_ascii [@inlined]) c
+
+let is_digit_ascii c = c > '\047' && c < '\058'
+let is_whitespace_ascii c = c = '\032' || (c > '\008' && c < '\014')

src/core/CCChar.mli

@@ -34,6 +34,32 @@ val pp_buf : Buffer.t -> t -> unit
 val pp : Format.formatter -> t -> unit
 (** Renamed from [print] since 2.0. *)
 
+val is_uppercase_ascii : t -> bool
+(** [is_uppercase_ascii c] is true exactly when  [c] is an
+    uppercase ASCII character, i.e. ['\064'] < [c] < ['\091'].
+    @since 3.16 *)
+
+val is_lowercase_ascii : t -> bool
+(** [is_lowercase_ascii c] is true exactly when [c] is a
+    lowercase ASCII character, i.e. ['\096'] < [c] < ['\123'].
+    @since 3.16 *)
+
+val is_letter_ascii : t -> bool
+(** [is_letter_ascii c] is true exactly when [c] is an ASCII
+    letter, i.e. [is_uppercase_ascii c || is_lowercase_ascii c].
+    @since 3.16 *)
+
+val is_digit_ascii : t -> bool
+(** [is_digit_ascii c] is true exactly when [c] is an
+    ASCII digit, i.e. ['\047'] < [c] < ['\058'].
+    @since 3.16 *)
+
+val is_whitespace_ascii : t -> bool
+(** [is_whitespace_ascii c] is true exactly when [c] is an ASCII
+    whitespace character as defined by Unicode, i.e. either [c = ' ']
+    or ['\008'] < [c] < ['\014'].
+    @since 3.16 *)
+
 (** {2 Infix Operators}
 
     @since 3.3 *)

src/core/CCEither.mli

@@ -2,7 +2,7 @@
 
 (** Either Monad
 
-    Module that is compatible with Either form OCaml 4.12 but can be use with any
+    Module that is compatible with Either from OCaml 4.12 but can be use with any
     ocaml version compatible with container
 
     @since 3.2

src/core/CCFormat.ml

@@ -32,7 +32,6 @@ let newline = Format.pp_force_newline
 let substring out (s, i, len) : unit = string out (String.sub s i len)
 let text = Format.pp_print_text
 let option = Format.pp_print_option
-let opt = option
 let result = Format.pp_print_result
 
 let string_lines out (s : string) : unit =
@@ -91,6 +90,11 @@ let iter ?(sep = return ",@ ") pp fmt seq =
         sep fmt ();
       pp fmt x)
 
+let opt pp fmt x =
+  match x with
+  | None -> Format.pp_print_string fmt "none"
+  | Some x -> Format.fprintf fmt "some %a" pp x
+
 let pair ?(sep = return ",@ ") ppa ppb fmt (a, b) =
   Format.fprintf fmt "%a%a%a" ppa a sep () ppb b
 

src/core/CCFormat.mli

@@ -100,13 +100,16 @@ val seq : ?sep:unit printer -> 'a printer -> 'a Seq.t printer
 val iter : ?sep:unit printer -> 'a printer -> 'a iter printer
 
 val option : ?none:unit printer -> 'a printer -> 'a option printer
-(** [opt ?none pp] prints options as follows:
+(** [option ?none pp] prints options as follows:
         - [Some x] will become [pp x]
         - [None] will become [none ()]
+    Alias of {!Format.pp_print_option}
     @since NEXT_RELEASE *)
 
-val opt : ?none:unit printer -> 'a printer -> 'a option printer
-(** Alias of {!option} *)
+val opt : 'a printer -> 'a option printer
+(** [opt pp] prints options as follows:
+    - [Some x] will become "some foo" if [pp x ---> "foo"].
+    - [None] will become "none". *)
 
 val result : ok:'a printer -> error:'e printer -> ('a, 'e) result printer
 

src/core/CCFun.ml

@@ -10,13 +10,7 @@ include Fun
 
 let[@inline] and_pred f g x = f x && g x
 let[@inline] or_pred f g x = f x || g x
-
-[@@@iflt 5.2]
-
-let[@inline] compose f g x = f (g x)
-
-[@@@endif]
-
+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
@@ -67,9 +61,16 @@ let rec iterate n f x =
   else
     iterate (n - 1) f (f x)
 
+let[@inline] with_return (type ret) f : ret =
+  let exception E of ret in
+  let return x = raise_notrace (E x) in
+  match f return with
+  | res -> res
+  | exception E res -> res
+
 module Infix = struct
   (* default implem for some operators *)
-  let ( %> ) f g = compose g f
+  let ( %> ) = compose
   let[@inline] ( % ) f g x = f (g x)
   let ( let@ ) = ( @@ )
   let ( ||> ) (a, b) f = f a b

src/core/CCFun.mli

@@ -17,13 +17,8 @@ val or_pred : ('a -> bool) -> ('a -> bool) -> 'a -> bool
     @since 3.13.1
 *)
 
-[@@@iflt 5.2]
-
-val compose : ('b -> 'c) -> ('a -> 'b) -> 'a -> 'c
-(** [compose f g x] is [f (g x)]. Composition.
-    @since NEXT_RELEASE arguments are inversted *)
-
-[@@@endif]
+val compose : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
+(** [compose f g x] is [g (f x)]. Composition. *)
 
 val compose_binop : ('a -> 'b) -> ('b -> 'b -> 'c) -> 'a -> 'a -> 'c
 (** [compose_binop f g] is [fun x y -> g (f x) (f y)].
@@ -83,14 +78,29 @@ val iterate : int -> ('a -> 'a) -> 'a -> 'a
     [x], [iterate 1 f x] is [f x], [iterate 2 f x] is [f (f x)], etc.
     @since 2.1 *)
 
+val with_return : (('ret -> 'a) -> 'ret) -> 'ret
+(** [with_return f] is [f return], where [return] is a function
+  that can be invoked to exit the scope early.
+
+  For example:
+{[
+let find_array arr x =
+  let@ return = with_return in
+  for i = 0 to Array.length arr-1 do
+    if arr.(i) = x then return i;
+  done;
+  -1
+]}
+
+  @since 3.15 *)
+
 (** {2 Infix}
 
     Infix operators. *)
 
 module Infix : sig
   val ( %> ) : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
-  (** [(f %> g) x] or [(%>) f g x] is [g (f x)]. Infix version of [compose].
-      The order of the arguments of [%>] and {!compose} are inverted. *)
+  (** [(f %> g) x] or [(%>) f g x] is [g (f x)]. Alias to [compose]. *)
 
   val ( % ) : ('b -> 'c) -> ('a -> 'b) -> 'a -> 'c
   (** [(f % g) x] or [(%) f g x] is [f (g x)]. Mathematical composition. *)

src/core/CCHash.ml

@@ -101,7 +101,7 @@ let max_len_b_ = 128
 
 let bytes (x : bytes) =
   let h = ref fnv_offset_basis in
-  for i = 0 to min max_len_b_ (Bytes.length x) do
+  for i = 0 to min max_len_b_ (Bytes.length x - 1) do
     (h := Int64.(mul !h fnv_prime));
     let byte = Char.code (Bytes.unsafe_get x i) in
     h := Int64.(logxor !h (of_int byte))

src/core/CCList.ml

@@ -752,6 +752,12 @@ let sorted_diff_uniq ~cmp l1 l2 =
   in
   recurse ~cmp [] l1 l2
 
+let rec drop n l =
+  match l with
+  | [] -> []
+  | _ when n = 0 -> l
+  | _ :: l' -> drop (n - 1) l'
+
 [@@@iflt 4.14]
 
 let take n l =
@@ -772,6 +778,8 @@ let take n l =
   in
   direct direct_depth_default_ n l
 
+let take_drop n l = take n l, drop n l
+
 [@@@else_]
 
 let[@tail_mod_cons] rec take n l =
@@ -783,20 +791,29 @@ let[@tail_mod_cons] rec take n l =
     else
       []
 
-[@@@endif]
+let take_drop n l =
+  (* fun idea from nojb in
+     https://discuss.ocaml.org/t/efficient-implementation-of-list-split/17616/2 *)
+  let[@tail_mod_cons] rec loop (res_drop : _ ref) n l =
+    match l with
+    | [] -> []
+    | x :: tl ->
+      if n = 0 then (
+        res_drop := l;
+        []
+      ) else
+        x :: loop res_drop (n - 1) tl
+  in
+  let res_drop = ref [] in
+  let res_take = loop res_drop n l in
+  res_take, !res_drop
 
-let rec drop n l =
-  match l with
-  | [] -> []
-  | _ when n = 0 -> l
-  | _ :: l' -> drop (n - 1) l'
+[@@@endif]
 
 let hd_tl = function
   | [] -> failwith "hd_tl"
   | x :: l -> x, l
 
-let take_drop n l = take n l, drop n l
-
 let sublists_of_len ?(last = fun _ -> None) ?offset n l =
   if n < 1 then invalid_arg "sublists_of_len: n must be > 0";
   let offset =

src/core/CCList.mli

@@ -375,7 +375,7 @@ val mguard : bool -> unit t
     @since 3.1 *)
 
 val return : 'a -> 'a t
-(** [return x] is [x]. *)
+(** [return x] is [[x]]. *)
 
 val take : int -> 'a t -> 'a t
 (** [take n l] takes the [n] first elements of the list [l], drop the rest. *)

src/core/CCMap.ml

@@ -20,47 +20,6 @@ module type S = sig
       and returns [default] otherwise (if [k] doesn't belong in [m]).
       @since 0.16 *)
 
-  val update : key -> ('a option -> 'a option) -> 'a t -> 'a t
-  (** [update k f m] calls [f (Some v)] if [find k m = v],
-      otherwise it calls [f None]. In any case, if the result is [None]
-      [k] is removed from [m], and if the result is [Some v'] then
-      [add k v' m] is returned. *)
-
-  val choose_opt : 'a t -> (key * 'a) option
-  (** [choose_opt m] returns one binding of the given map [m], or [None] if [m] is empty.
-      Safe version of {!choose}.
-      @since 1.5 *)
-
-  val min_binding_opt : 'a t -> (key * 'a) option
-  (** [min_binding_opt m] returns the smallest binding of the given map [m],
-      or [None] if [m] is empty.
-      Safe version of {!min_binding}.
-      @since 1.5 *)
-
-  val max_binding_opt : 'a t -> (key * 'a) option
-  (** [max_binding_opt m] returns the largest binding of the given map [m],
-      or [None] if [m] is empty.
-      Safe version of {!max_binding}.
-      @since 1.5 *)
-
-  val find_opt : key -> 'a t -> 'a option
-  (** [find_opt k m] returns [Some v] if the current binding of [k] in [m] is [v],
-      or [None] if the key [k] is not present.
-      Safe version of {!find}.
-      @since 1.5 *)
-
-  val find_first : (key -> bool) -> 'a t -> key * 'a
-  (** [find_first f m] where [f] is a monotonically increasing function, returns the binding of [m]
-      with the lowest key [k] such that [f k], or raises [Not_found] if no such key exists.
-      See {!Map.S.find_first}.
-      @since 1.5 *)
-
-  val find_first_opt : (key -> bool) -> 'a t -> (key * 'a) option
-  (** [find_first_opt f m] where [f] is a monotonically increasing function, returns an option containing
-      the binding of [m] with the lowest key [k] such that [f k], or [None] if no such key exists.
-      Safe version of {!find_first}.
-      @since 1.5 *)
-
   val merge_safe :
     f:(key -> [ `Left of 'a | `Right of 'b | `Both of 'a * 'b ] -> 'c option) ->
     'a t ->
@@ -69,24 +28,12 @@ module type S = sig
   (** [merge_safe ~f a b] merges the maps [a] and [b] together.
       @since 0.17 *)
 
-  val add_seq : 'a t -> (key * 'a) Seq.t -> 'a t
-  (** [add_seq m seq] adds the given [Seq.t] of bindings to the map [m].
-      Like {!add_list}.
-      Renamed from [add_std_seq] since 3.0.
-      @since 3.0 *)
-
   val add_seq_with :
     f:(key -> 'a -> 'a -> 'a) -> 'a t -> (key * 'a) Seq.t -> 'a t
   (** [add_seq ~f m l] adds the given seq [l] of bindings to the map [m],
       using [f] to combine values that have the same key.
       @since 3.3 *)
 
-  val of_seq : (key * 'a) Seq.t -> 'a t
-  (** [of_seq seq] builds a map from the given [Seq.t] of bindings.
-      Like {!of_list}.
-      Renamed from [of_std_seq] since 3.0.
-      @since 3.0 *)
-
   val of_seq_with : f:(key -> 'a -> 'a -> 'a) -> (key * 'a) Seq.t -> 'a t
   (** [of_seq_with ~f l] builds a map from the given seq [l] of bindings [k_i -> v_i],
       added in order using {!add}.
@@ -178,62 +125,6 @@ module Make (O : Map.OrderedType) = struct
   (* backport functions from recent stdlib.
      they will be shadowed by inclusion of [S] if present. *)
 
-  [@@@ocaml.warning "-32"]
-
-  let union f a b =
-    M.merge
-      (fun k v1 v2 ->
-        match v1, v2 with
-        | None, None -> assert false
-        | None, (Some _ as r) -> r
-        | (Some _ as r), None -> r
-        | Some v1, Some v2 -> f k v1 v2)
-      a b
-
-  let update k f m =
-    let x = try f (Some (M.find k m)) with Not_found -> f None in
-    match x with
-    | None -> M.remove k m
-    | Some v' -> M.add k v' m
-
-  let choose_opt m = try Some (M.choose m) with Not_found -> None
-  let find_opt k m = try Some (M.find k m) with Not_found -> None
-  let max_binding_opt m = try Some (M.max_binding m) with Not_found -> None
-  let min_binding_opt m = try Some (M.min_binding m) with Not_found -> None
-
-  exception Find_binding_exit
-
-  let find_first_opt f m =
-    let res = ref None in
-    try
-      M.iter
-        (fun k v ->
-          if f k then (
-            res := Some (k, v);
-            raise Find_binding_exit
-          ))
-        m;
-      None
-    with Find_binding_exit -> !res
-
-  let find_first f m =
-    match find_first_opt f m with
-    | None -> raise Not_found
-    | Some (k, v) -> k, v
-
-  (* linear time, must traverse the whole map… *)
-  let find_last_opt f m =
-    let res = ref None in
-    M.iter (fun k v -> if f k then res := Some (k, v)) m;
-    !res
-
-  let find_last f m =
-    match find_last_opt f m with
-    | None -> raise Not_found
-    | Some (k, v) -> k, v
-
-  [@@@ocaml.warning "+32"]
-
   (* === include M.
      This will shadow some values depending on OCaml's current version
      === *)
@@ -253,11 +144,6 @@ module Make (O : Map.OrderedType) = struct
         | Some v1, Some v2 -> f k (`Both (v1, v2)))
       a b
 
-  let add_seq m s =
-    let m = ref m in
-    Seq.iter (fun (k, v) -> m := add k v !m) s;
-    !m
-
   let add_seq_with ~f m s =
     let combine k v = function
       | None -> Some v
@@ -265,7 +151,6 @@ module Make (O : Map.OrderedType) = struct
     in
     Seq.fold_left (fun m (k, v) -> update k (combine k v) m) m s
 
-  let of_seq s = add_seq empty s
   let of_seq_with ~f s = add_seq_with ~f empty s
 
   let add_iter m s =
@@ -296,10 +181,20 @@ module Make (O : Map.OrderedType) = struct
     in
     List.fold_left (fun m (k, v) -> update k (combine k v) m) m l
 
+  [@@@iflt 5.1]
+
   let of_list l = add_list empty l
+
+  [@@@endif]
+
   let of_list_with ~f l = add_list_with ~f empty l
+
+  [@@@iflt 5.1]
+
   let to_list m = fold (fun k v acc -> (k, v) :: acc) m []
 
+  [@@@endif]
+
   let pp ?(pp_start = fun _ () -> ()) ?(pp_stop = fun _ () -> ())
       ?(pp_arrow = fun fmt () -> Format.fprintf fmt "@ -> ")
       ?(pp_sep = fun fmt () -> Format.fprintf fmt ",@ ") pp_k pp_v fmt m =

src/core/CCMap.mli

@@ -16,6 +16,7 @@ module type OrderedType = Map.OrderedType
 
 module type S = sig
   include Map.S
+  (** @inline *)
 
   val get : key -> 'a t -> 'a option
   (** [get k m] returns [Some v] if the current binding of [k] in [m] is [v],
@@ -27,47 +28,6 @@ module type S = sig
       and returns [default] otherwise (if [k] doesn't belong in [m]).
       @since 0.16 *)
 
-  val update : key -> ('a option -> 'a option) -> 'a t -> 'a t
-  (** [update k f m] calls [f (Some v)] if [find k m = v],
-      otherwise it calls [f None]. In any case, if the result is [None]
-      [k] is removed from [m], and if the result is [Some v'] then
-      [add k v' m] is returned. *)
-
-  val choose_opt : 'a t -> (key * 'a) option
-  (** [choose_opt m] returns one binding of the given map [m], or [None] if [m] is empty.
-      Safe version of {!choose}.
-      @since 1.5 *)
-
-  val min_binding_opt : 'a t -> (key * 'a) option
-  (** [min_binding_opt m] returns the smallest binding of the given map [m],
-      or [None] if [m] is empty.
-      Safe version of {!min_binding}.
-      @since 1.5 *)
-
-  val max_binding_opt : 'a t -> (key * 'a) option
-  (** [max_binding_opt m] returns the largest binding of the given map [m],
-      or [None] if [m] is empty.
-      Safe version of {!max_binding}.
-      @since 1.5 *)
-
-  val find_opt : key -> 'a t -> 'a option
-  (** [find_opt k m] returns [Some v] if the current binding of [k] in [m] is [v],
-      or [None] if the key [k] is not present.
-      Safe version of {!find}.
-      @since 1.5 *)
-
-  val find_first : (key -> bool) -> 'a t -> key * 'a
-  (** [find_first f m] where [f] is a monotonically increasing function, returns the binding of [m]
-      with the lowest key [k] such that [f k], or raises [Not_found] if no such key exists.
-      See {!Map.S.find_first}.
-      @since 1.5 *)
-
-  val find_first_opt : (key -> bool) -> 'a t -> (key * 'a) option
-  (** [find_first_opt f m] where [f] is a monotonically increasing function, returns an option containing
-      the binding of [m] with the lowest key [k] such that [f k], or [None] if no such key exists.
-      Safe version of {!find_first}.
-      @since 1.5 *)
-
   val merge_safe :
     f:(key -> [ `Left of 'a | `Right of 'b | `Both of 'a * 'b ] -> 'c option) ->
     'a t ->
@@ -76,12 +36,6 @@ module type S = sig
   (** [merge_safe ~f a b] merges the maps [a] and [b] together.
       @since 0.17 *)
 
-  val add_seq : 'a t -> (key * 'a) Seq.t -> 'a t
-  (** [add_seq m seq] adds the given [Seq.t] of bindings to the map [m].
-      Like {!add_list}.
-      Renamed from [add_std_seq] since 3.0.
-      @since 3.0 *)
-
   val add_seq_with :
     f:(key -> 'a -> 'a -> 'a) -> 'a t -> (key * 'a) Seq.t -> 'a t
   (** [add_seq ~f m l] adds the given seq [l] of bindings to the map [m],
@@ -91,12 +45,6 @@ module type S = sig
       later in the seq than [v2].
       @since 3.3 *)
 
-  val of_seq : (key * 'a) Seq.t -> 'a t
-  (** [of_seq seq] builds a map from the given [Seq.t] of bindings.
-      Like {!of_list}.
-      Renamed from [of_std_seq] since 3.0.
-      @since 3.0 *)
-
   val of_seq_with : f:(key -> 'a -> 'a -> 'a) -> (key * 'a) Seq.t -> 'a t
   (** [of_seq_with ~f l] builds a map from the given seq [l] of bindings [k_i -> v_i],
       added in order using {!add}.

src/core/CCNativeint.ml

@@ -2,8 +2,13 @@
 
 include Nativeint
 
+[@@@iflt 4.13]
+
 let min : t -> t -> t = Stdlib.min
 let max : t -> t -> t = Stdlib.max
+
+[@@@endif]
+
 let hash x = Stdlib.abs (to_int x)
 let sign i = compare i zero
 
@@ -95,8 +100,7 @@ let random_range i j st = add i (random (sub j i) st)
 (** {2 Conversion} *)
 
 let of_string_exn = of_string
-let of_string x = try Some (of_string_exn x) with Failure _ -> None
-let of_string_opt = of_string
+let of_string = of_string_opt
 let most_significant_bit = logxor (neg 1n) (shift_right_logical (neg 1n) 1)
 
 type output = char -> unit

src/core/CCNativeint.mli

@@ -2,14 +2,14 @@
 
 (** Helpers for processor-native integers
 
-    This module provides operations on the type [nativeint] of signed 32-bit integers 
-    (on 32-bit platforms) or signed 64-bit integers (on 64-bit platforms). 
-    This integer type has exactly the same width as that of a pointer type in the C compiler. 
-    All arithmetic operations over nativeint are taken modulo 2{^32} or 2{^64} depending 
+    This module provides operations on the type [nativeint] of signed 32-bit integers
+    (on 32-bit platforms) or signed 64-bit integers (on 64-bit platforms).
+    This integer type has exactly the same width as that of a pointer type in the C compiler.
+    All arithmetic operations over nativeint are taken modulo 2{^32} or 2{^64} depending
     on the word size of the architecture.
 
-    Performance notice: values of type [nativeint] occupy more memory space than values of type [int], 
-    and arithmetic operations on [nativeint] are generally slower than those on [int]. 
+    Performance notice: values of type [nativeint] occupy more memory space than values of type [int],
+    and arithmetic operations on [nativeint] are generally slower than those on [int].
     Use [nativeint] only when the application requires the extra bit of precision over the [int] type.
 
     @since 2.1 *)
@@ -18,6 +18,7 @@
 include module type of struct
   include Nativeint
 end
+(** @inline *)
 
 val min : t -> t -> t
 (** [min x y] returns the minimum of the two integers [x] and [y].
@@ -117,7 +118,7 @@ val pp_binary : t printer
 
 module Infix : sig
   val ( + ) : t -> t -> t
-  (** [x + y] is the sum of [x] and [y]. 
+  (** [x + y] is the sum of [x] and [y].
       Addition. *)
 
   val ( - ) : t -> t -> t

src/core/CCOption.ml

@@ -2,11 +2,7 @@
 
 (** {1 Options} *)
 
-type 'a t = 'a option
-
-let[@inline] map f = function
-  | None -> None
-  | Some x -> Some (f x)
+include Option
 
 let map_or ~default f = function
   | None -> default
@@ -16,30 +12,7 @@ let map_lazy default_fn f = function
   | None -> default_fn ()
   | Some x -> f x
 
-let is_some = function
-  | None -> false
-  | Some _ -> true
-
-let is_none = function
-  | None -> true
-  | Some _ -> false
-
-let compare f o1 o2 =
-  match o1, o2 with
-  | None, None -> 0
-  | Some _, None -> 1
-  | None, Some _ -> -1
-  | Some x, Some y -> f x y
-
-let equal f o1 o2 =
-  match o1, o2 with
-  | None, None -> true
-  | Some _, None | None, Some _ -> false
-  | Some x, Some y -> f x y
-
 let return x = Some x
-let some = return
-let none = None
 
 let[@inline] flat_map f o =
   match o with
@@ -51,7 +24,6 @@ let[@inline] flat_map_l f o =
   | None -> []
   | Some x -> f x
 
-let[@inline] bind o f = flat_map f o
 let ( >>= ) = bind
 let pure x = Some x
 let k_compose f g x = f x |> flat_map g
@@ -99,11 +71,6 @@ let for_all p = function
   | None -> true
   | Some x -> p x
 
-let iter f o =
-  match o with
-  | None -> ()
-  | Some x -> f x
-
 let fold f acc o =
   match o with
   | None -> acc
@@ -121,11 +88,6 @@ let apply_or f x =
 
 let ( |?> ) x f = apply_or f x
 
-let value x ~default =
-  match x with
-  | None -> default
-  | Some y -> y
-
 let get_exn = function
   | Some x -> x
   | None -> invalid_arg "CCOption.get_exn"
@@ -164,11 +126,6 @@ let wrap2 ?(handler = fun _ -> true) f x y =
     else
       raise e
 
-let to_list o =
-  match o with
-  | None -> []
-  | Some x -> [ x ]
-
 let of_list = function
   | x :: _ -> Some x
   | [] -> None
@@ -254,11 +211,6 @@ let to_iter o k =
   | None -> ()
   | Some x -> k x
 
-let to_seq o () =
-  match o with
-  | None -> Seq.Nil
-  | Some x -> Seq.Cons (x, Seq.empty)
-
 let pp ppx out = function
   | None -> Format.pp_print_string out "None"
   | Some x -> Format.fprintf out "@[Some %a@]" ppx x

src/core/CCOption.mli

@@ -5,10 +5,8 @@
    This module replaces `CCOpt`.
    @since 3.6 *)
 
-type +'a t = 'a option
-
-val map : ('a -> 'b) -> 'a t -> 'b t
-(** [map f o] applies the function [f] to the element inside [o], if any. *)
+include module type of Option
+(** @inline *)
 
 val map_or : default:'b -> ('a -> 'b) -> 'a t -> 'b
 (** [map_or ~default f o] is [f x] if [o = Some x], [default] otherwise.
@@ -18,33 +16,9 @@ val map_lazy : (unit -> 'b) -> ('a -> 'b) -> 'a t -> 'b
 (** [map_lazy default_fn f o] is [f x] if [o = Some x], [default_fn ()] otherwise.
     @since 1.2 *)
 
-val is_some : _ t -> bool
-(** [is_some (Some x)] returns [true] otherwise it returns [false]. *)
-
-val is_none : _ t -> bool
-(** [is_none None] returns [true] otherwise it returns [false].
-    @since 0.11 *)
-
-val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
-(** [compare comp o1 o2] compares two options [o1] and [o2],
-    using custom comparators [comp] for the value.
-    [None] is always assumed to be less than [Some _]. *)
-
-val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
-(** [equal p o1 o2] tests for equality between option types [o1] and [o2],
-    using a custom equality predicate [p]. *)
-
 val return : 'a -> 'a t
 (** [return x] is a monadic return, that is [return x = Some x]. *)
 
-val some : 'a -> 'a t
-(** Alias to {!return}.
-    @since 3.5 *)
-
-val none : 'a t
-(** Alias to {!None}.
-    @since 3.5 *)
-
 val flat_map : ('a -> 'b t) -> 'a t -> 'b t
 (** [flat_map f o] is equivalent to {!map} followed by {!flatten}.
     Flip version of {!(>>=)}. *)
@@ -53,11 +27,6 @@ val flat_map_l : ('a -> 'b list) -> 'a t -> 'b list
 (** [flat_map_l f o] is [[]] if [o] is [None], or [f x] if [o] is [Some x].
     @since 3.12 *)
 
-val bind : 'a t -> ('a -> 'b t) -> 'b t
-(** [bind o f] is [f v] if [o] is [Some v], [None] otherwise.
-    Monadic bind.
-    @since 3.0 *)
-
 val k_compose : ('a -> 'b t) -> ('b -> 'c t) -> 'a -> 'c t
 (** Kleisli composition. Monadic equivalent of {!CCFun.compose}
       @since 3.13.1 *)
@@ -65,9 +34,6 @@ val k_compose : ('a -> 'b t) -> ('b -> 'c t) -> 'a -> 'c t
 val map2 : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
 (** [map2 f o1 o2] maps ['a option] and ['b option] to a ['c option] using [f]. *)
 
-val iter : ('a -> unit) -> 'a t -> unit
-(** [iter f o] applies [f] to [o]. Iterate on 0 or 1 element. *)
-
 val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
 (** [fold f init o] is [f init x] if [o] is [Some x], or [init] if [o] is [None].
     Fold on 0 or 1 element. *)
@@ -102,10 +68,6 @@ val apply_or : ('a -> 'a t) -> 'a -> 'a
     turning functions like "remove" into "remove_if_it_exists".
     @since 3.13.1 *)
 
-val value : 'a t -> default:'a -> 'a
-(** [value o ~default] is similar to the Stdlib's [Option.value] and to {!get_or}.
-    @since 2.8 *)
-
 val get_exn : 'a t -> 'a
 [@@ocaml.deprecated "use CCOption.get_exn_or instead"]
 (** [get_exn o] returns [x] if [o] is [Some x] or fails if [o] is [None].
@@ -207,9 +169,6 @@ include module type of Infix
 
 (** {2 Conversion and IO} *)
 
-val to_list : 'a t -> 'a list
-(** [to_list o] returns [[x]] if [o] is [Some x] or the empty list [[]] if [o] is [None]. *)
-
 val of_list : 'a list -> 'a t
 (** [of_list l] returns [Some x] (x being the head of the list l), or [None] if [l] is the empty list. *)
 
@@ -246,13 +205,6 @@ val to_gen : 'a t -> 'a gen
 (** [to_gen o] is [o] as a [gen]. [Some x] is the singleton [gen] containing [x]
     and [None] is the empty [gen]. *)
 
-val to_seq : 'a t -> 'a Seq.t
-(** [to_seq o] is [o] as a sequence [Seq.t]. [Some x] is the singleton sequence containing [x]
-    and [None] is the empty sequence.
-    Same as {!Stdlib.Option.to_seq}
-    Renamed from [to_std_seq] since 3.0.
-    @since 3.0 *)
-
 val to_iter : 'a t -> 'a iter
 (** [to_iter o] returns an internal iterator, like in the library [Iter].
     @since 2.8 *)

src/core/CCPair.ml

@@ -2,27 +2,53 @@
 
 (** {1 Tuple Functions} *)
 
+[@@@ifge 5.4]
+
+include Pair
+
+[@@@else_]
+
 type ('a, 'b) t = 'a * 'b
 
 let make x y = x, y
+let fst = fst
+let snd = snd
+let swap (x, y) = y, x
 let map_fst f (x, y) = f x, y
 let map_snd f (x, y) = x, f y
 let map f g (x, y) = f x, g y
+
+[@@@endif]
+
 let map_same f (x, y) = f x, f y
 let map2 f g (a, b) (x, y) = f a x, g b y
 let map_same2 f (a, b) (x, y) = f a x, f b y
 let fst_map f (x, _) = f x
 let snd_map f (_, x) = f x
+
+[@@@iflt 5.4]
+
 let iter f (x, y) = f x y
-let swap (x, y) = y, x
+
+[@@@endif]
+
 let ( <<< ) = map_fst
 let ( >>> ) = map_snd
 let ( *** ) = map
 let ( &&& ) f g x = f x, g x
 let merge f (x, y) = f x y
+
+[@@@iflt 5.4]
+
 let fold = merge
+
+[@@@endif]
+
 let dup x = x, x
 let dup_map f x = x, f x
+
+[@@@iflt 5.4]
+
 let equal f g (x1, y1) (x2, y2) = f x1 x2 && g y1 y2
 
 let compare f g (x1, y1) (x2, y2) =
@@ -32,6 +58,8 @@ let compare f g (x1, y1) (x2, y2) =
   else
     g y1 y2
 
+[@@@endif]
+
 let to_string ?(sep = ", ") a_to_string b_to_string (x, y) =
   Printf.sprintf "%s%s%s" (a_to_string x) sep (b_to_string y)
 

src/core/CCPair.mli

@@ -2,12 +2,28 @@
 
 (** Tuple Functions *)
 
+[@@@ifge 5.4]
+
+include module type of Pair
+(** @inline *)
+
+[@@@else_]
+
 type ('a, 'b) t = 'a * 'b
 
 val make : 'a -> 'b -> ('a, 'b) t
 (** Make a tuple from its components.
     @since 0.16 *)
 
+val fst : 'a * 'b -> 'a
+(** [fst (a, b)] returns [a] *)
+
+val snd : 'a * 'b -> 'b
+(** [snd (a, b)] returns [b] *)
+
+val swap : 'a * 'b -> 'b * 'a
+(** Swap the components of the tuple. *)
+
 val map_fst : ('a -> 'b) -> 'a * 'c -> 'b * 'c
 (** [map_fst f (x, y)] returns [(f x, y)].
     Renamed from [map1] since 3.0. *)
@@ -19,6 +35,8 @@ val map_snd : ('a -> 'b) -> 'c * 'a -> 'c * 'b
 val map : ('a -> 'c) -> ('b -> 'd) -> 'a * 'b -> 'c * 'd
 (** Synonym to {!( *** )}. Map on both sides of a tuple. *)
 
+[@@@endif]
+
 val map_same : ('a -> 'b) -> 'a * 'a -> 'b * 'b
 (** Like {!map} but specialized for pairs with elements of the same type. *)
 
@@ -45,10 +63,11 @@ val snd_map : ('a -> 'b) -> _ * 'a -> 'b
     Rename from [map_snd] since 3.0.
     @since 0.3.3 *)
 
+[@@@iflt 5.4]
+
 val iter : ('a -> 'b -> unit) -> 'a * 'b -> unit
 
-val swap : 'a * 'b -> 'b * 'a
-(** Swap the components of the tuple. *)
+[@@@endif]
 
 val ( <<< ) : ('a -> 'b) -> 'a * 'c -> 'b * 'c
 (** Map on the left side of the tuple. *)
@@ -66,10 +85,14 @@ val ( &&& ) : ('a -> 'b) -> ('a -> 'c) -> 'a -> 'b * 'c
 val merge : ('a -> 'b -> 'c) -> 'a * 'b -> 'c
 (** Uncurrying (merges the two components of a tuple). *)
 
+[@@@iflt 5.4]
+
 val fold : ('a -> 'b -> 'c) -> 'a * 'b -> 'c
 (** Synonym to {!merge}.
     @since 0.3.3 *)
 
+[@@@endif]
+
 val dup : 'a -> 'a * 'a
 (** [dup x = (x,x)] (duplicate the value).
     @since 0.3.3 *)
@@ -79,12 +102,16 @@ val dup_map : ('a -> 'b) -> 'a -> 'a * 'b
     to the second copy.
     @since 0.3.3 *)
 
+[@@@iflt 5.4]
+
 val equal :
   ('a -> 'a -> bool) -> ('b -> 'b -> bool) -> 'a * 'b -> 'a * 'b -> bool
 
 val compare :
   ('a -> 'a -> int) -> ('b -> 'b -> int) -> 'a * 'b -> 'a * 'b -> int
 
+[@@@endif]
+
 val to_string :
   ?sep:string -> ('a -> string) -> ('b -> string) -> 'a * 'b -> string
 (** Print tuple in a string

src/core/CCResult.ml

@@ -9,13 +9,7 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Basics} *)
 
-type nonrec (+'good, +'bad) result = ('good, 'bad) result =
-  | Ok of 'good
-  | Error of 'bad
-
-type (+'good, +'bad) t = ('good, 'bad) result =
-  | Ok of 'good
-  | Error of 'bad
+include Result
 
 let return x = Ok x
 let fail s = Error s
@@ -65,30 +59,14 @@ let opt_map f e =
     | Ok x -> Ok (Some x)
     | Error e -> Error e)
 
-let map f e =
-  match e with
-  | Ok x -> Ok (f x)
-  | Error s -> Error s
-
-let map_err f e =
-  match e with
-  | Ok _ as res -> res
-  | Error y -> Error (f y)
+let map_err = map_error
 
 let map2 f g e =
   match e with
   | Ok x -> Ok (f x)
   | Error s -> Error (g s)
 
-let iter f e =
-  match e with
-  | Ok x -> f x
-  | Error _ -> ()
-
-let iter_err f e =
-  match e with
-  | Ok _ -> ()
-  | Error err -> f err
+let iter_err = iter_error
 
 exception Get_error
 
@@ -132,6 +110,13 @@ let flat_map f e =
   | Ok x -> f x
   | Error s -> Error s
 
+[@@@iflt 5.4]
+
+let retract = function
+  | Ok v | Error v -> v
+
+[@@@endif]
+
 let k_compose f g x = f x |> flat_map g
 let ( >=> ) = k_compose
 let ( <=< ) f g = g >=> f
@@ -149,24 +134,11 @@ let compare ~err cmp a b =
   | _, Ok _ -> -1
   | Error s, Error s' -> err s s'
 
-let fold ~ok ~error x =
-  match x with
-  | Ok x -> ok x
-  | Error s -> error s
-
 let fold_ok f acc r =
   match r with
   | Ok x -> f acc x
   | Error _ -> acc
 
-let is_ok = function
-  | Ok _ -> true
-  | Error _ -> false
-
-let is_error = function
-  | Ok _ -> false
-  | Error _ -> true
-
 (** {2 Wrappers} *)
 
 let guard f = try Ok (f ()) with e -> Error e
@@ -185,18 +157,18 @@ let ( <*> ) f x =
   | Error s -> fail s
   | Ok f -> map f x
 
-let join t =
-  match t with
-  | Ok (Ok o) -> Ok o
-  | Ok (Error e) -> Error e
-  | Error _ as e -> e
+[@@@iflt 5.4]
 
-let both x y =
+let product x y =
   match x, y with
   | Ok o, Ok o' -> Ok (o, o')
   | Ok _, Error e -> Error e
   | Error e, _ -> Error e
 
+[@@@endif]
+
+let both = product
+
 (** {2 Collections} *)
 
 let map_l f l =
@@ -331,19 +303,12 @@ end
 
 (** {2 Conversions} *)
 
-let to_opt = function
-  | Ok x -> Some x
-  | Error _ -> None
+let to_opt = to_option
 
 let of_opt = function
   | None -> Error "of_opt"
   | Some x -> Ok x
 
-let to_seq e () =
-  match e with
-  | Ok x -> Seq.Cons (x, Seq.empty)
-  | Error _ -> Seq.Nil
-
 let to_iter e k =
   match e with
   | Ok x -> k x

src/core/CCResult.mli

@@ -16,13 +16,8 @@ type 'a printer = Format.formatter -> 'a -> unit
 
 (** {2 Basics} *)
 
-type nonrec (+'good, +'bad) result = ('good, 'bad) result =
-  | Ok of 'good
-  | Error of 'bad
-
-type (+'good, +'bad) t = ('good, 'bad) result =
-  | Ok of 'good
-  | Error of 'bad
+include module type of Result
+(** @inline *)
 
 val return : 'a -> ('a, 'err) t
 (** Successfully return a value. *)
@@ -68,22 +63,15 @@ val opt_map : ('a -> ('b, 'c) t) -> 'a option -> ('b option, 'c) t
 (** Map a fallible operation through an option.
     @since 3.7 *)
 
-val map : ('a -> 'b) -> ('a, 'err) t -> ('b, 'err) t
-(** Map on success. *)
-
 val map_err : ('err1 -> 'err2) -> ('a, 'err1) t -> ('a, 'err2) t
-(** Map on the error variant. *)
+(** Alias of [map_error] *)
 
 val map2 : ('a -> 'b) -> ('err1 -> 'err2) -> ('a, 'err1) t -> ('b, 'err2) t
 (** Like {!map}, but also with a function that can transform
     the error message in case of failure. *)
 
-val iter : ('a -> unit) -> ('a, _) t -> unit
-(** Apply the function only in case of [Ok]. *)
-
 val iter_err : ('err -> unit) -> (_, 'err) t -> unit
-(** Apply the function in case of [Error].
-    @since 2.4 *)
+(** Alias of {!iter_error} *)
 
 exception Get_error
 
@@ -120,6 +108,13 @@ val catch : ('a, 'err) t -> ok:('a -> 'b) -> err:('err -> 'b) -> 'b
 
 val flat_map : ('a -> ('b, 'err) t) -> ('a, 'err) t -> ('b, 'err) t
 
+[@@@iflt 5.4]
+
+val retract : ('a, 'a) t -> 'a
+(** [retract r] collapse [r] to [v] if [r] is either [Ok v] or [Error v]. *)
+
+[@@@endif]
+
 val k_compose :
   ('a -> ('b, 'err) t) -> ('b -> ('c, 'err) t) -> 'a -> ('c, 'err) t
 (** Kleisli composition. Monadic equivalent of {!CCFun.compose}.
@@ -128,23 +123,11 @@ val k_compose :
 val equal : err:'err equal -> 'a equal -> ('a, 'err) t equal
 val compare : err:'err ord -> 'a ord -> ('a, 'err) t ord
 
-val fold : ok:('a -> 'b) -> error:('err -> 'b) -> ('a, 'err) t -> 'b
-(** [fold ~ok ~error e] opens [e] and, if [e = Ok x], returns
-    [ok x], otherwise [e = Error s] and it returns [error s]. *)
-
 val fold_ok : ('a -> 'b -> 'a) -> 'a -> ('b, _) t -> 'a
 (** [fold_ok f acc r] will compute [f acc x] if [r=Ok x],
     and return [acc] otherwise, as if the result were a mere option.
     @since 1.2 *)
 
-val is_ok : ('a, 'err) t -> bool
-(** Return true if [Ok].
-    @since 1.0 *)
-
-val is_error : ('a, 'err) t -> bool
-(** Return true if [Error].
-    @since 1.0 *)
-
 (** {2 Wrappers} *)
 
 val guard : (unit -> 'a) -> ('a, exn) t
@@ -172,15 +155,18 @@ val wrap3 : ('a -> 'b -> 'c -> 'd) -> 'a -> 'b -> 'c -> ('d, exn) t
 val pure : 'a -> ('a, 'err) t
 (** Synonym of {!return}. *)
 
-val join : (('a, 'err) t, 'err) t -> ('a, 'err) t
-(** [join t], in case of success, returns [Ok o] from [Ok (Ok o)]. Otherwise,
-    it fails with [Error e] where [e] is the unwrapped error of [t]. *)
+[@@@iflt 5.4]
 
-val both : ('a, 'err) t -> ('b, 'err) t -> ('a * 'b, 'err) t
-(** [both a b], in case of success, returns [Ok (o, o')] with the ok values
+val product : ('a, 'err) t -> ('b, 'err) t -> ('a * 'b, 'err) t
+(** [product a b], in case of success, returns [Ok (o, o')] with the ok values
     of [a] and [b]. Otherwise, it fails, and the error of [a] is chosen over the
     error of [b] if both fail. *)
 
+[@@@endif]
+
+val both : ('a, 'err) t -> ('b, 'err) t -> ('a * 'b, 'err) t
+(** Alias of {!product} *)
+
 (** {2 Infix} *)
 
 module Infix : sig
@@ -279,7 +265,7 @@ end
 (** {2 Conversions} *)
 
 val to_opt : ('a, _) t -> 'a option
-(** Convert a result to an option. *)
+(** Alias of {!to_option} *)
 
 val of_opt : 'a option -> ('a, string) t
 (** [of_opt opt] converts [Some v] to [Ok v] and [None] to [Error "of_opt"].*)
@@ -287,10 +273,6 @@ val of_opt : 'a option -> ('a, string) t
 val to_iter : ('a, _) t -> 'a iter
 (** @since 2.8 *)
 
-val to_seq : ('a, _) t -> 'a Seq.t
-(** Renamed from [to_std_seq] since 3.0.
-    @since 3.0 *)
-
 type ('a, 'b) error =
   [ `Ok of 'a
   | `Error of 'b

src/core/CCSeq.ml

@@ -9,10 +9,19 @@ type 'a printer = Format.formatter -> 'a -> unit
 include Seq
 
 let nil () = Nil
+
+[@@@iflt 4.11]
+
 let cons a b () = Cons (a, b)
-let empty = nil
+
+[@@@endif]
+[@@@iflt 5.4]
+
 let singleton x () = Cons (x, nil)
 
+[@@@endif]
+[@@@iflt 4.11]
+
 let init n f =
   let rec aux i () =
     if i >= n then
@@ -22,6 +31,8 @@ let init n f =
   in
   aux 0
 
+[@@@endif]
+
 let rec _forever x () = Cons (x, _forever x)
 
 let rec _repeat n x () =
@@ -37,11 +48,15 @@ let repeat ?n x =
 
 let rec forever f () = Cons (f (), forever f)
 
+[@@@iflt 4.14]
+
 let is_empty l =
   match l () with
   | Nil -> true
   | Cons _ -> false
 
+[@@@endif]
+
 let head_exn l =
   match l () with
   | Nil -> raise Not_found
@@ -62,11 +77,15 @@ let tail l =
   | Nil -> None
   | Cons (_, l) -> Some l
 
+[@@@iflt 4.14]
+
 let uncons l =
   match l () with
   | Nil -> None
   | Cons (h, t) -> Some (h, t)
 
+[@@@endif]
+
 let rec equal eq l1 l2 =
   match l1 (), l2 () with
   | Nil, Nil -> true
@@ -100,14 +119,9 @@ let foldi f acc res =
   in
   aux acc 0 res
 
-let fold_lefti = foldi
+[@@@iflt 4.14]
 
-let rec iter f l =
-  match l () with
-  | Nil -> ()
-  | Cons (x, l') ->
-    f x;
-    iter f l'
+let fold_lefti = foldi
 
 let iteri f l =
   let rec aux f l i =
@@ -151,11 +165,6 @@ let rec drop_while p l () =
   | Cons (x, l') when p x -> drop_while p l' ()
   | Cons _ as res -> res
 
-let rec map f l () =
-  match l () with
-  | Nil -> Nil
-  | Cons (x, l') -> Cons (f x, map f l')
-
 let mapi f l =
   let rec aux f l i () =
     match l () with
@@ -164,36 +173,55 @@ let mapi f l =
   in
   aux f l 0
 
-let rec fmap f (l : 'a t) () =
-  match l () with
-  | Nil -> Nil
-  | Cons (x, l') ->
-    (match f x with
-    | None -> fmap f l' ()
-    | Some y -> Cons (y, fmap f l'))
+[@@@endif]
+[@@@iflt 5.4]
 
-let rec filter p l () =
-  match l () with
-  | Nil -> Nil
-  | Cons (x, l') ->
-    if p x then
-      Cons (x, filter p l')
-    else
-      filter p l' ()
+let filteri f l =
+  let rec aux f l i () =
+    match l () with
+    | Nil -> Nil
+    | Cons (x, tl) ->
+      if f i x then
+        Cons (x, aux f tl (i + 1))
+      else
+        aux f tl (i + 1) ()
+  in
+  aux f l 0
+
+[@@@endif]
+
+let fmap = filter_map
+
+[@@@iflt 4.11]
 
 let rec append l1 l2 () =
   match l1 () with
   | Nil -> l2 ()
   | Cons (x, l1') -> Cons (x, append l1' l2)
 
-let rec cycle l () = append l (cycle l) ()
+[@@@endif]
+[@@@iflt 4.14]
+
+let rec cycle l =
+  if is_empty l then
+    l
+  else
+    fun () ->
+  append l (cycle l) ()
+
 let rec iterate f a () = Cons (a, iterate f (f a))
 
+[@@@endif]
+[@@@iflt 4.11]
+
 let rec unfold f acc () =
   match f acc with
   | None -> Nil
   | Some (x, acc') -> Cons (x, unfold f acc')
 
+[@@@endif]
+[@@@iflt 4.14]
+
 let rec for_all p l =
   match l () with
   | Nil -> true
@@ -221,6 +249,35 @@ let rec find_map f l =
     | None -> find_map f tl
     | e -> e)
 
+[@@@endif]
+[@@@iflt 5.1]
+
+let find_index p l =
+  let rec aux i l =
+    match l () with
+    | Nil -> None
+    | Cons (x, tl) ->
+      if p x then
+        Some i
+      else
+        aux (i + 1) tl
+  in
+  aux 0 l
+
+let find_mapi f l =
+  let rec aux i l =
+    match l () with
+    | Nil -> None
+    | Cons (x, tl) ->
+      (match f i x with
+      | Some _ as res -> res
+      | None -> aux (i + 1) tl)
+  in
+  aux 0 l
+
+[@@@endif]
+[@@@iflt 5.1]
+
 let rec scan f acc res () =
   Cons
     ( acc,
@@ -229,18 +286,13 @@ let rec scan f acc res () =
         | Nil -> Nil
         | Cons (s, cont) -> scan f (f acc s) cont () )
 
-let rec flat_map f l () =
-  match l () with
-  | Nil -> Nil
-  | Cons (x, l') -> _flat_map_app f (f x) l' ()
-
-and _flat_map_app f l l' () =
-  match l () with
-  | Nil -> flat_map f l' ()
-  | Cons (x, tl) -> Cons (x, _flat_map_app f tl l')
+[@@@endif]
+[@@@iflt 4.13]
 
 let concat_map = flat_map
 
+[@@@endif]
+
 let product_with f l1 l2 =
   let rec _next_left h1 tl1 h2 tl2 () =
     match tl1 () with
@@ -264,6 +316,8 @@ let product_with f l1 l2 =
   in
   _next_left [] l1 [] l2
 
+[@@@iflt 4.14]
+
 let map_product = product_with
 let product l1 l2 = product_with (fun x y -> x, y) l1 l2
 
@@ -273,6 +327,8 @@ let rec group eq l () =
   | Cons (x, l') ->
     Cons (cons x (take_while (eq x) l'), group eq (drop_while (eq x) l'))
 
+[@@@endif]
+
 let rec _uniq eq prev l () =
   match prev, l () with
   | _, Nil -> Nil
@@ -285,16 +341,13 @@ let rec _uniq eq prev l () =
 
 let uniq eq l = _uniq eq None l
 
-let rec filter_map f l () =
-  match l () with
-  | Nil -> Nil
-  | Cons (x, l') ->
-    (match f x with
-    | None -> filter_map f l' ()
-    | Some y -> Cons (y, filter_map f l'))
+[@@@iflt 4.13]
 
-let flatten l = flat_map (fun x -> x) l
-let concat = flatten
+let concat l = flat_map (fun x -> x) l
+
+[@@@endif]
+
+let flatten = concat
 
 let range i j =
   let rec aux i j () =
@@ -317,12 +370,18 @@ let ( --^ ) i j =
   else
     range i (j + 1)
 
-let rec fold2 f acc l1 l2 =
+[@@@iflt 4.14]
+
+let rec fold_left2 f acc l1 l2 =
   match l1 (), l2 () with
   | Nil, _ | _, Nil -> acc
-  | Cons (x1, l1'), Cons (x2, l2') -> fold2 f (f acc x1 x2) l1' l2'
+  | Cons (x1, l1'), Cons (x2, l2') -> fold_left2 f (f acc x1 x2) l1' l2'
 
-let fold_left2 = fold2
+[@@@endif]
+
+let fold2 = fold_left2
+
+[@@@iflt 4.14]
 
 let rec map2 f l1 l2 () =
   match l1 (), l2 () with
@@ -346,17 +405,21 @@ let rec exists2 f l1 l2 =
   | Nil, _ | _, Nil -> false
   | Cons (x1, l1'), Cons (x2, l2') -> f x1 x2 || exists2 f l1' l2'
 
-let rec merge cmp l1 l2 () =
+let rec sorted_merge cmp l1 l2 () =
   match l1 (), l2 () with
   | Nil, tl2 -> tl2
   | tl1, Nil -> tl1
   | Cons (x1, l1'), Cons (x2, l2') ->
     if cmp x1 x2 < 0 then
-      Cons (x1, merge cmp l1' l2)
+      Cons (x1, sorted_merge cmp l1' l2)
     else
-      Cons (x2, merge cmp l1 l2')
+      Cons (x2, sorted_merge cmp l1 l2')
 
-let sorted_merge = merge
+[@@@endif]
+
+let merge = sorted_merge
+
+[@@@iflt 4.14]
 
 let rec zip a b () =
   match a (), b () with
@@ -377,6 +440,8 @@ let unzip l =
 
 let split = unzip
 
+[@@@endif]
+
 let zip_i seq =
   let rec loop i seq () =
     match seq () with
@@ -387,7 +452,6 @@ let zip_i seq =
 
 (** {2 Implementations} *)
 
-let return x () = Cons (x, nil)
 let pure = return
 let ( >>= ) xs f = flat_map f xs
 let ( >|= ) xs f = map f xs
@@ -530,11 +594,15 @@ let rec memoize f =
 
 (** {2 Fair Combinations} *)
 
+[@@@iflt 4.14]
+
 let rec interleave a b () =
   match a () with
   | Nil -> b ()
   | Cons (x, tail) -> Cons (x, interleave b tail)
 
+[@@@endif]
+
 let rec fair_flat_map f a () =
   match a () with
   | Nil -> Nil

src/core/CCSeq.mli

@@ -17,38 +17,60 @@ include module type of Seq
 (** @inline *)
 
 val nil : 'a t
-val empty : 'a t
+
+[@@@iflt 4.11]
+
 val cons : 'a -> 'a t -> 'a t
+
+[@@@endif]
+[@@@iflt 5.4]
+
 val singleton : 'a -> 'a t
 
+[@@@endif]
+[@@@iflt 4.14]
+
 val init : int -> (int -> 'a) -> 'a t
 (** [init n f] corresponds to the sequence [f 0; f 1; ...; f (n-1)].
     @raise Invalid_argument if n is negative.
     @since 3.10 *)
 
+[@@@endif]
+
 val repeat : ?n:int -> 'a -> 'a t
 (** [repeat ~n x] repeats [x] [n] times then stops. If [n] is omitted,
     then [x] is repeated forever. *)
 
+[@@@iflt 4.14]
+
 val forever : (unit -> 'a) -> 'a t
 (** [forever f] corresponds to the infinite sequence containing all the [f ()].
     @since 3.10 *)
 
 val cycle : 'a t -> 'a t
-(** Cycle through the iterator infinitely. The iterator shouldn't be empty. *)
+(** Cycle through the sequence infinitely. The sequence should be persistent.
+  @since NEXT_RELEASE the sequence can be empty, in this case cycle return an empty sequence. *)
 
 val iterate : ('a -> 'a) -> 'a -> 'a t
 (** [iterate f a] corresponds to the infinite sequence containing [a], [f a], [f (f a)],
     ...
     @since 3.10 *)
 
+[@@@endif]
+[@@@iflt 4.11]
+
 val unfold : ('b -> ('a * 'b) option) -> 'b -> 'a t
 (** [unfold f acc] calls [f acc] and:
     - if [f acc = Some (x, acc')], yield [x], continue with [unfold f acc'].
     - if [f acc = None], stops. *)
 
+[@@@endif]
+[@@@iflt 4.14]
+
 val is_empty : 'a t -> bool
-(** [is_empty xs] checks in the sequence [xs] is empty *)
+(** [is_empty xs] checks in the sequence [xs] is empty. [is_empty] acces the first element of the sequence, this can causes issue if the sequence is ephemeral. *)
+
+[@@@endif]
 
 val head : 'a t -> 'a option
 (** Head of the list. *)
@@ -64,10 +86,14 @@ val tail_exn : 'a t -> 'a t
 (** Unsafe version of {!tail}.
     @raise Not_found if the list is empty. *)
 
+[@@@iflt 4.14]
+
 val uncons : 'a t -> ('a * 'a t) option
 (** [uncons xs] return [None] if [xs] is empty other
     @since 3.10 *)
 
+[@@@endif]
+
 val equal : 'a equal -> 'a t equal
 (** Equality step by step. Eager. *)
 
@@ -86,12 +112,12 @@ val foldi : ('a -> int -> 'b -> 'a) -> 'a -> 'b t -> 'a
     0) and [x] is the element of the sequence.
     @since 3.10 *)
 
+[@@@iflt 4.14]
+
 val fold_lefti : ('a -> int -> 'b -> 'a) -> 'a -> 'b t -> 'a
 (** Alias of {!foldi}.
     @since 3.10 *)
 
-val iter : ('a -> unit) -> 'a t -> unit
-
 val iteri : (int -> 'a -> unit) -> 'a t -> unit
 (** Iterate with index (starts at 0). *)
 
@@ -104,19 +130,33 @@ val take : int -> 'a t -> 'a t
 val take_while : ('a -> bool) -> 'a t -> 'a t
 val drop : int -> 'a t -> 'a t
 val drop_while : ('a -> bool) -> 'a t -> 'a t
-val map : ('a -> 'b) -> 'a t -> 'b t
 
 val mapi : (int -> 'a -> 'b) -> 'a t -> 'b t
 (** Map with index (starts at 0). *)
 
+[@@@endif]
+[@@@iflt 5.4]
+
+val filteri : (int -> 'a -> bool) -> 'a t -> 'a t
+(** Similar to {!filter} but the predicate takes aditionally the index of the elements. *)
+
+[@@@endif]
+
 val fmap : ('a -> 'b option) -> 'a t -> 'b t
-val filter : ('a -> bool) -> 'a t -> 'a t
+(** Alias of {!filter_map}. *)
+
+[@@@iflt 4.11]
+
 val append : 'a t -> 'a t -> 'a t
 
+[@@@endif]
+
 val product_with : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
 (** Fair product of two (possibly infinite) lists into a new list. Lazy.
     The first parameter is used to combine each pair of elements. *)
 
+[@@@iflt 4.14]
+
 val map_product : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
 (** Alias of {!product_with}.
     @since 3.10 *)
@@ -129,11 +169,15 @@ val group : 'a equal -> 'a t -> 'a t t
     For instance [group (=) [1;1;1;2;2;3;3;1]] yields
       [[1;1;1]; [2;2]; [3;3]; [1]]. *)
 
+[@@@endif]
+
 val uniq : 'a equal -> 'a t -> 'a t
 (** [uniq eq l] returns [l] but removes consecutive duplicates. Lazy.
     In other words, if several values that are equal follow one another,
     only the first of them is kept. *)
 
+[@@@iflt 4.14]
+
 val for_all : ('a -> bool) -> 'a t -> bool
 (** [for_all p [a1; ...; an]] checks if all elements of the sequence satisfy the
     predicate [p].  That is, it returns [(p a1) && ... && (p an)] for a
@@ -158,23 +202,37 @@ val find_map : ('a -> 'b option) -> 'a t -> 'b option
     [f ai = Some _] and return [None] otherwise.
     @since 3.10 *)
 
+[@@@endif]
+[@@@iflt 5.1]
+
+val find_index : ('a -> bool) -> 'a t -> int option
+(** [find_index p xs] returns [Some i], where [i] is the index of the first value of [xs] satisfying [p]. It returns [None] if no value of [xs] satifies [p]. *)
+
+val find_mapi : (int -> 'a -> 'b option) -> 'a t -> 'b option
+(** Similar to {!find_map} but the predicate take aditionnaly the index of the element. *)
+
+[@@@endif]
+[@@@iflt 4.14]
+
 val scan : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a t
 (** [scan f init xs] is the sequence containing the intermediate result of
     [fold f init xs].
     @since 3.10 *)
 
-val flat_map : ('a -> 'b t) -> 'a t -> 'b t
+[@@@endif]
+[@@@iflt 4.13]
 
 val concat_map : ('a -> 'b t) -> 'a t -> 'b t
 (** Alias of {!flat_map}
     @since 3.10 *)
 
-val filter_map : ('a -> 'b option) -> 'a t -> 'b t
-val flatten : 'a t t -> 'a t
-
 val concat : 'a t t -> 'a t
-(** Alias of {!flatten}.
-    @since 3.10 *)
+(** @since 3.10 *)
+
+[@@@endif]
+
+val flatten : 'a t t -> 'a t
+(** Alias of {!concat} *)
 
 val range : int -> int -> int t
 
@@ -183,16 +241,22 @@ val ( -- ) : int -> int -> int t
     [a] and [b] (therefore, never empty). *)
 
 val ( --^ ) : int -> int -> int t
-(** [a -- b] is the integer range from [a] to [b], where [b] is excluded. *)
+(** [a --^ b] is the integer range from [a] to [b], where [b] is excluded. *)
 
 (** {2 Operations on two Collections} *)
 
-val fold2 : ('acc -> 'a -> 'b -> 'acc) -> 'acc -> 'a t -> 'b t -> 'acc
-(** Fold on two collections at once. Stop as soon as one of them ends. *)
+[@@@iflt 4.14]
 
 val fold_left2 : ('acc -> 'a -> 'b -> 'acc) -> 'acc -> 'a t -> 'b t -> 'acc
-(** Alias for {!fold2}.
-    @since 3.10 *)
+(** Fold on two collections at once. Stop as soon as one of them ends.
+@since 3.10 *)
+
+[@@@endif]
+
+val fold2 : ('acc -> 'a -> 'b -> 'acc) -> 'acc -> 'a t -> 'b t -> 'acc
+(** Alias for {!fold_left2}. *)
+
+[@@@iflt 4.14]
 
 val map2 : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
 (** Map on two collections at once. Stop as soon as one of the
@@ -204,12 +268,19 @@ val iter2 : ('a -> 'b -> unit) -> 'a t -> 'b t -> unit
 val for_all2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> bool
 val exists2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> bool
 
-val merge : 'a ord -> 'a t -> 'a t -> 'a t
-(** Merge two sorted iterators into a sorted iterator. *)
+[@@@endif]
+[@@@iflt 4.14]
 
 val sorted_merge : 'a ord -> 'a t -> 'a t -> 'a t
-(** Alias of {!merge}.
-    @since 3.10 *)
+(** Merge two sorted iterators into a sorted iterator.
+  @since 3.10 *)
+
+[@@@endif]
+
+val merge : 'a ord -> 'a t -> 'a t -> 'a t
+(** Alias of {!sorted_merge}. *)
+
+[@@@iflt 4.14]
 
 val zip : 'a t -> 'b t -> ('a * 'b) t
 (** Combine elements pairwise. Stop as soon as one of the lists stops. *)
@@ -221,6 +292,8 @@ val split : ('a * 'b) t -> 'a t * 'b t
 (** Alias of {!unzip}.
     @since 3.10 *)
 
+[@@@endif]
+
 val zip_i : 'a t -> (int * 'a) t
 (** [zip_i seq] zips the index of each element with the element itself.
     @since 3.8
@@ -241,9 +314,13 @@ val memoize : 'a t -> 'a t
 
 (** {2 Fair Combinations} *)
 
+[@@@iflt 4.14]
+
 val interleave : 'a t -> 'a t -> 'a t
 (** Fair interleaving of both streams. *)
 
+[@@@endif]
+
 val fair_flat_map : ('a -> 'b t) -> 'a t -> 'b t
 (** Fair version of {!flat_map}. *)
 
@@ -252,7 +329,6 @@ val fair_app : ('a -> 'b) t -> 'a t -> 'b t
 
 (** {2 Implementations} *)
 
-val return : 'a -> 'a t
 val pure : 'a -> 'a t
 val ( >>= ) : 'a t -> ('a -> 'b t) -> 'b t
 val ( >|= ) : 'a t -> ('a -> 'b) -> 'b t

src/core/CCSet.ml

@@ -10,43 +10,11 @@ module type OrderedType = Set.OrderedType
 module type S = sig
   include Set.S
 
-  val min_elt_opt : t -> elt option
-  (** Safe version of {!min_elt}.
-      @since 1.5 *)
-
-  val max_elt_opt : t -> elt option
-  (** Safe version of {!max_elt}.
-      @since 1.5 *)
-
-  val choose_opt : t -> elt option
-  (** Safe version of {!choose}.
-      @since 1.5 *)
-
-  val find_opt : elt -> t -> elt option
-  (** Safe version of {!find}.
-      @since 1.5 *)
-
-  val find_first : (elt -> bool) -> t -> elt
-  (** Find minimum element satisfying predicate.
-      @since 1.5 *)
-
-  val find_first_opt : (elt -> bool) -> t -> elt option
-  (** Safe version of {!find_first}.
-      @since 1.5 *)
-
   val find_first_map : (elt -> 'a option) -> t -> 'a option
   (** [find_first_map f s] find the minimum element [x] of [s] such that [f x = Some y]
       and return [Some y]. Otherwise returns [None].
       @since 3.12 *)
 
-  val find_last : (elt -> bool) -> t -> elt
-  (** Find maximum element satisfying predicate.
-      @since 1.5 *)
-
-  val find_last_opt : (elt -> bool) -> t -> elt option
-  (** Safe version of {!find_last}.
-      @since 1.5 *)
-
   val find_last_map : (elt -> 'a option) -> t -> 'a option
   (** [find_last_map f s] find the maximum element [x] of [s] such that [f x = Some y]
       and return [Some y]. Otherwise returns [None].
@@ -56,16 +24,9 @@ module type S = sig
   (** Build a set from the given [iter] of elements.
       @since 2.8 *)
 
-  val of_seq : elt Seq.t -> t
-  (** Build a set from the given [seq] of elements.
-      @since 3.0 *)
-
   val add_iter : t -> elt iter -> t
   (** @since 2.8 *)
 
-  val add_seq : elt Seq.t -> t -> t
-  (** @since 3.0 *)
-
   val to_iter : t -> elt iter
   (** [to_iter t] converts the set [t] to a [iter] of the elements.
       @since 2.8 *)
@@ -103,31 +64,8 @@ module Make (O : Map.OrderedType) = struct
 
   [@@@ocaml.warning "-32"]
 
-  let find_opt x s = try Some (S.find x s) with Not_found -> None
-  let choose_opt s = try Some (S.choose s) with Not_found -> None
-  let min_elt_opt s = try Some (S.min_elt s) with Not_found -> None
-  let max_elt_opt s = try Some (S.max_elt s) with Not_found -> None
-
   exception Find_binding_exit
 
-  let find_first_opt f m =
-    let res = ref None in
-    try
-      S.iter
-        (fun x ->
-          if f x then (
-            res := Some x;
-            raise Find_binding_exit
-          ))
-        m;
-      None
-    with Find_binding_exit -> !res
-
-  let find_first f m =
-    match find_first_opt f m with
-    | None -> raise Not_found
-    | Some x -> x
-
   let find_first_map f m =
     let res = ref None in
     try
@@ -142,22 +80,10 @@ module Make (O : Map.OrderedType) = struct
       None
     with Find_binding_exit -> !res
 
-  (* linear time, must traverse the whole set… *)
-  let find_last_opt f m =
-    let res = ref None in
-    S.iter (fun x -> if f x then res := Some x) m;
-    !res
-
-  let find_last f m =
-    match find_last_opt f m with
-    | None -> raise Not_found
-    | Some x -> x
-
   [@@@ocaml.warning "+32"]
 
   include S
 
-  (* Use find_last which is linear time on OCaml < 4.05 *)
   let find_last_map f m =
     let res = ref None in
     let _ =
@@ -172,13 +98,6 @@ module Make (O : Map.OrderedType) = struct
     in
     !res
 
-  let add_seq seq set =
-    let set = ref set in
-    Seq.iter (fun x -> set := add x !set) seq;
-    !set
-
-  let of_seq s = add_seq s empty
-
   let add_iter set i =
     let set = ref set in
     i (fun x -> set := add x !set);

src/core/CCSet.mli

@@ -16,43 +16,11 @@ module type OrderedType = Set.OrderedType
 module type S = sig
   include Set.S
 
-  val min_elt_opt : t -> elt option
-  (** Safe version of {!min_elt}.
-      @since 1.5 *)
-
-  val max_elt_opt : t -> elt option
-  (** Safe version of {!max_elt}.
-      @since 1.5 *)
-
-  val choose_opt : t -> elt option
-  (** Safe version of {!choose}.
-      @since 1.5 *)
-
-  val find_opt : elt -> t -> elt option
-  (** Safe version of {!find}.
-      @since 1.5 *)
-
-  val find_first : (elt -> bool) -> t -> elt
-  (** Find minimum element satisfying predicate.
-      @since 1.5 *)
-
-  val find_first_opt : (elt -> bool) -> t -> elt option
-  (** Safe version of {!find_first}.
-      @since 1.5 *)
-
   val find_first_map : (elt -> 'a option) -> t -> 'a option
   (** [find_first_map f s] find the minimum element [x] of [s] such that [f x = Some y]
       and return [Some y]. Otherwise returns [None].
       @since 3.12 *)
 
-  val find_last : (elt -> bool) -> t -> elt
-  (** Find maximum element satisfying predicate.
-      @since 1.5 *)
-
-  val find_last_opt : (elt -> bool) -> t -> elt option
-  (** Safe version of {!find_last}.
-      @since 1.5 *)
-
   val find_last_map : (elt -> 'a option) -> t -> 'a option
   (** [find_last_map f s] find the maximum element [x] of [s] such that [f x = Some y]
       and return [Some y]. Otherwise returns [None].
@@ -62,16 +30,9 @@ module type S = sig
   (** Build a set from the given [iter] of elements.
       @since 2.8 *)
 
-  val of_seq : elt Seq.t -> t
-  (** Build a set from the given [seq] of elements.
-      @since 3.0 *)
-
   val add_iter : t -> elt iter -> t
   (** @since 2.8 *)
 
-  val add_seq : elt Seq.t -> t -> t
-  (** @since 3.0 *)
-
   val to_iter : t -> elt iter
   (** [to_iter t] converts the set [t] to a [iter] of the elements.
       @since 2.8 *)

src/core/CCString.ml

@@ -585,6 +585,24 @@ let take n s =
   else
     s
 
+let take_while f s =
+  let i = ref 0 in
+  while !i < String.length s && f (String.unsafe_get s !i) do
+    incr i
+  done;
+  String.sub s 0 !i
+
+let rtake_while f s =
+  let s_len_pred = String.length s - 1 in
+  let i = ref s_len_pred in
+  while !i >= 0 && f (String.unsafe_get s !i) do
+    decr i
+  done;
+  if !i < s_len_pred then
+    String.sub s (!i + 1) (s_len_pred - !i)
+  else
+    ""
+
 let drop n s =
   if n < String.length s then
     String.sub s n (String.length s - n)
@@ -674,24 +692,11 @@ let of_gen g =
 
 let to_iter s k = String.iter k s
 
-let rec _to_seq s i len () =
-  if len = 0 then
-    Seq.Nil
-  else
-    Seq.Cons (s.[i], _to_seq s (i + 1) (len - 1))
-
-let to_seq s = _to_seq s 0 (String.length s)
-
 let of_iter i =
   let b = Buffer.create 32 in
   i (Buffer.add_char b);
   Buffer.contents b
 
-let of_seq seq =
-  let b = Buffer.create 32 in
-  Seq.iter (Buffer.add_char b) seq;
-  Buffer.contents b
-
 let to_list s = _to_list s [] 0 (String.length s)
 
 let of_list l =

src/core/CCString.mli

@@ -49,11 +49,6 @@ val to_iter : t -> char iter
 (** [to_iter s] returns the [iter] of characters contained in the string [s].
     @since 2.8 *)
 
-val to_seq : t -> char Seq.t
-(** [to_seq s] returns the [Seq.t] of characters contained in the string [s].
-    Renamed from [to std_seq] since 3.0.
-    @since 3.0 *)
-
 val to_list : t -> char list
 (** [to_list s] returns the [list] of characters contained in the string [s]. *)
 
@@ -98,11 +93,6 @@ val of_iter : char iter -> string
 (** [of_iter iter] converts an [iter] of characters to a string.
     @since 2.8 *)
 
-val of_seq : char Seq.t -> string
-(** [of_seq seq] converts a [seq] of characters to a string.
-    Renamed from [of_std_seq] since 3.0.
-    @since 3.0 *)
-
 val of_list : char list -> string
 (** [of_list lc] converts a list of characters [lc] to a string. *)
 
@@ -113,7 +103,7 @@ val to_array : string -> char array
 (** [to_array s] returns the array of characters contained in the string [s]. *)
 
 val find : ?start:int -> sub:string -> string -> int
-(** [find ~start ~sub s] returns the starting index of the first occurrence of [sub] within [s] or [-1]. 
+(** [find ~start ~sub s] returns the starting index of the first occurrence of [sub] within [s] or [-1].
     @param start starting position in [s]. *)
 
 val find_all : ?start:int -> sub:string -> string -> int gen
@@ -182,6 +172,16 @@ val take : int -> string -> string
 (** [take n s] keeps only the [n] first chars of [s].
     @since 0.17 *)
 
+val take_while : (char -> bool) -> string -> string
+(** [take_while f s] keeps only the longest prefix [t] of [s] such that every
+    character [c] in [t] satisfies [f c].
+    @since 3.16 *)
+
+val rtake_while : (char -> bool) -> string -> string
+(** [rtake_while f s] keeps only the longest suffix [t] of [s] such that every
+    character [c] in [t] satisfies [f c].
+    @since 3.16 *)
+
 val drop : int -> string -> string
 (** [drop n s] removes the [n] first chars of [s].
     @since 0.17 *)
@@ -462,10 +462,6 @@ module Split : sig
       @since 0.16 *)
 end
 
-val split_on_char : char -> string -> string list
-(** [split_on_char by s] splits the string [s] along the given char [by].
-    @since 1.2 *)
-
 val split : by:string -> string -> string list
 (** [split ~by s] splits the string [s] along the given string [by].
     Alias to {!Split.list_cpy}.

src/core/CCStringLabels.mli

@@ -49,11 +49,6 @@ val to_iter : t -> char iter
 (** [to_iter s] returns the [iter] of characters contained in the string [s].
     @since 2.8 *)
 
-val to_seq : t -> char Seq.t
-(** [to_seq s] returns the [Seq.t] of characters contained in the string [s].
-    Renamed from [to std_seq] since 3.0.
-    @since 3.0 *)
-
 val to_list : t -> char list
 (** [to_list s] returns the [list] of characters contained in the string [s]. *)
 
@@ -103,11 +98,6 @@ val of_iter : char iter -> string
 (** [of_iter iter] converts an [iter] of characters to a string.
     @since 2.8 *)
 
-val of_seq : char Seq.t -> string
-(** [of_seq seq] converts a [seq] of characters to a string.
-    Renamed from [of_std_seq] since 3.0.
-    @since 3.0 *)
-
 val of_list : char list -> string
 (** [of_list lc] converts a list of characters [lc] to a string. *)
 
@@ -118,7 +108,7 @@ val to_array : string -> char array
 (** [to_array s] returns the array of characters contained in the string [s]. *)
 
 val find : ?start:int -> sub:(string[@keep_label]) -> string -> int
-(** [find ?start ~sub s] returns the starting index of the first occurrence of [sub] within [s] or [-1]. 
+(** [find ?start ~sub s] returns the starting index of the first occurrence of [sub] within [s] or [-1].
     @param start starting position in [s]. *)
 
 val find_all : ?start:int -> sub:(string[@keep_label]) -> string -> int gen
@@ -193,6 +183,16 @@ val take : int -> string -> string
 (** [take n s] keeps only the [n] first chars of [s].
     @since 0.17 *)
 
+val take_while : f:(char -> bool) -> string -> string
+(** [take_while ~f s] keeps only the longest prefix [t] of [s] such that every
+    character [c] in [t] satisfies [f c].
+    @since 3.16 *)
+
+val rtake_while : f:(char -> bool) -> string -> string
+(** [rtake_while ~f s] keeps only the longest suffix [t] of [s] such that every
+    character [c] in [t] satisfies [f c].
+    @since 3.16 *)
+
 val drop : int -> string -> string
 (** [drop n s] removes the [n] first chars of [s].
     @since 0.17 *)
@@ -502,10 +502,6 @@ module Split : sig
       @since 0.16 *)
 end
 
-val split_on_char : by:char -> string -> string list
-(** [split_on_char ~by s] splits the string [s] along the given char [by].
-    @since 1.2 *)
-
 val split : by:(string[@keep_label]) -> string -> string list
 (** [split ~by s] splits the string [s] along the given string [by].
     Alias to {!Split.list_cpy}.

src/core/CCUtf8_string.ml

@@ -65,8 +65,10 @@ let next_ (type a) (st : Dec.t) ~(yield : uchar -> a) ~(stop : unit -> a) () : a
       (* except for first, each char gives 6 bits *)
       let next = (acc lsl 6) lor (c land 0b111111) in
       if j = n_bytes then
-        if (* done reading the codepoint *)
-           Uchar.is_valid next then (
+        if
+          (* done reading the codepoint *)
+          Uchar.is_valid next
+        then (
           st.i <- st.i + j + 1;
           (* +1 for first char *)
           yield (Uchar.unsafe_of_int next)

src/core/CCVector.mli

@@ -222,7 +222,7 @@ val find : ('a -> bool) -> ('a, _) t -> 'a option
 
 val findi : ('a -> bool) -> ('a, _) t -> (int * 'a) option
 (** Find an element and its index that satisfies the predicate.
-    @since NEXT_RELEASE *)
+    @since 3.15 *)
 
 val find_exn : ('a -> bool) -> ('a, _) t -> 'a
 (** Find an element that satisfies the predicate, or

src/core/dune

@@ -6,7 +6,7 @@
   (action
    (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
  (flags :standard -nolabels -open CCMonomorphic)
- (libraries either containers.monomorphic))
+ (libraries either containers.monomorphic containers.domain))
 
 (ocamllex
  (modules CCSexp_lex))

src/core/tests/test_random.ml

@@ -31,5 +31,5 @@ let uniformity_test ?(size_hint = 10) k rng st =
 
 let () =
   let st = Random.State.make_self_init () in
-  let ok = run ~st (uniformity_test 50_000 (split_list 10 ~len:3)) in
+  let ok = run ~st (uniformity_test 500_000 (split_list 10 ~len:3)) in
   if not ok then failwith "uniformity check failed"

src/data/CCFQueue.ml

@@ -37,8 +37,7 @@ let _empty = Shallow Zero
 let _single x = Shallow (One x)
 let _double x y = Shallow (Two (x, y))
 
-let _deep :
-    type l0 l1.
+let _deep : type l0 l1.
     int ->
     ('a, l0 succ) digit ->
     ('a * 'a) t lazy_t ->

src/data/CCFQueue.mli

@@ -139,7 +139,7 @@ val ( -- ) : int -> int -> int t
     @since 0.10 *)
 
 val ( --^ ) : int -> int -> int t
-(** [a -- b] is the integer range from [a] to [b], where [b] is excluded.
+(** [a --^ b] is the integer range from [a] to [b], where [b] is excluded.
     @since 0.17 *)
 
 val pp : 'a printer -> 'a t printer

src/data/CCGraph.ml

@@ -221,8 +221,7 @@ module Traverse = struct
       ]
 
     type ('v, 'e) t =
-      [ `Enter of
-        'v * int * ('v, 'e) path
+      [ `Enter of 'v * int * ('v, 'e) path
         (* unique index in traversal, path from start *)
       | `Exit of 'v
       | `Edge of 'v * 'e * 'v * edge_kind

src/data/CCGraph.mli

@@ -150,8 +150,7 @@ module Traverse : sig
       ]
 
     type ('v, 'e) t =
-      [ `Enter of
-        'v * int * ('v, 'e) path
+      [ `Enter of 'v * int * ('v, 'e) path
         (* unique index in traversal, path from start *)
       | `Exit of 'v
       | `Edge of 'v * 'e * 'v * edge_kind

src/data/CCHashTrie.ml

@@ -202,8 +202,10 @@ module A_SPARSE = struct
          let open Stdlib in
          Array.blit a.arr real_idx arr (real_idx + 1) (n - real_idx));
       { a with bits; arr }
-    ) else if (* replace element at [real_idx] *)
-              mut then (
+    ) else if
+        (* replace element at [real_idx] *)
+        mut
+      then (
       a.arr.(real_idx) <- x;
       a
     ) else (

src/domain/containers_domain.mli

@@ -0,0 +1,7 @@
+(** A partial stub for {!Domain}. *)
+
+val is_main_domain : unit -> bool
+val cpu_relax : unit -> unit
+
+val relax_loop : int -> unit
+(** Call {!cpu_relax} n times *)

src/domain/dune

@@ -0,0 +1,14 @@
+(library
+ (name containers_domain)
+ (synopsis "Compatibility library for the Domain module")
+ (public_name containers.domain)
+ (modules containers_domain))
+
+(executable
+ (modules gen)
+ (name gen))
+
+(rule
+ (targets containers_domain.ml)
+ (action
+  (run ./gen.exe)))

src/domain/gen.ml

@@ -0,0 +1,28 @@
+let domain_4 =
+  {|
+let is_main_domain () = true
+let cpu_relax = ignore
+let relax_loop : int -> unit = ignore
+  |}
+
+let domain_5 =
+  {|
+let is_main_domain = Domain.is_main_domain
+let cpu_relax = Domain.cpu_relax
+let relax_loop i =
+  for _j = 1 to i do cpu_relax () done
+|}
+
+let write_file file s =
+  let oc = open_out file in
+  output_string oc s;
+  close_out oc
+
+let () =
+  let version = Scanf.sscanf Sys.ocaml_version "%d.%d.%s" (fun x y _ -> x, y) in
+  write_file "containers_domain.ml"
+    (if version >= (5, 0) then
+       domain_5
+     else
+       domain_4);
+  ()

src/leb128/containers_leb128.ml

@@ -0,0 +1,98 @@
+(* adapted from ocaml-protoc from code by c-cube *)
+
+module Byte_slice = CCByte_slice
+module Byte_buffer = CCByte_buffer
+
+module Decode = struct
+  let skip (sl : Byte_slice.t) off : int =
+    let shift = ref 0 in
+    let continue = ref true in
+
+    let off = ref off in
+    let n_consumed = ref 0 in
+
+    while !continue do
+      if sl.len <= 0 then invalid_arg "out of bound";
+      incr n_consumed;
+      let b = Char.code (Bytes.get sl.bs !off) in
+      let cur = b land 0x7f in
+      if cur <> b then (
+        (* at least one byte follows this one *)
+        incr off;
+        shift := !shift + 7
+      ) else if !shift < 63 || b land 0x7f <= 1 then
+        continue := false
+      else
+        invalid_arg "leb128 varint is too long"
+    done;
+
+    !n_consumed
+
+  let u64 (sl : Byte_slice.t) (off : int) : int64 * int =
+    let shift = ref 0 in
+    let res = ref 0L in
+    let continue = ref true in
+
+    let off = ref off in
+    let n_consumed = ref 0 in
+
+    while !continue do
+      if sl.len <= 0 then invalid_arg "out of bound";
+      incr n_consumed;
+      let b = Char.code (Bytes.get sl.bs !off) in
+      let cur = b land 0x7f in
+      if cur <> b then (
+        (* at least one byte follows this one *)
+        (res := Int64.(logor !res (shift_left (of_int cur) !shift)));
+        incr off;
+        shift := !shift + 7
+      ) else if !shift < 63 || b land 0x7f <= 1 then (
+        (res := Int64.(logor !res (shift_left (of_int b) !shift)));
+        continue := false
+      ) else
+        invalid_arg "leb128 varint is too long"
+    done;
+
+    !res, !n_consumed
+
+  let[@inline] uint_truncate sl off =
+    let v, n_consumed = u64 sl off in
+    Int64.to_int v, n_consumed
+
+  let[@inline] decode_zigzag (v : int64) : int64 =
+    Int64.(logxor (shift_right v 1) (neg (logand v Int64.one)))
+
+  let[@inline] i64 sl off : int64 * int =
+    let v, n_consumed = u64 sl off in
+    decode_zigzag v, n_consumed
+
+  let[@inline] int_truncate sl off =
+    let v, n_consumed = u64 sl off in
+    Int64.to_int (decode_zigzag v), n_consumed
+end
+
+module Encode = struct
+  let[@inline] encode_zigzag (i : int64) : int64 =
+    Int64.(logxor (shift_left i 1) (shift_right i 63))
+
+  external varint_size : (int64[@unboxed]) -> int
+    = "caml_cc_leb128_varint_size_byte" "caml_cc_leb128_varint_size"
+  [@@noalloc]
+  (** Compute how many bytes this int would occupy as varint *)
+
+  external varint_slice : bytes -> (int[@untagged]) -> (int64[@unboxed]) -> unit
+    = "caml_cc_leb128_varint_byte" "caml_cc_leb128_varint"
+  [@@noalloc]
+  (** Write this int as varint into the given slice *)
+
+  let[@inline] u64 (buf : Byte_buffer.t) (i : int64) =
+    let n = varint_size i in
+    Byte_buffer.ensure_free buf n;
+    assert (buf.len + n <= Bytes.length buf.bs);
+    varint_slice buf.bs buf.len i;
+    buf.len <- buf.len + n
+
+  let[@inline] i64 buf i : unit = u64 buf (encode_zigzag i)
+  let[@inline] uint buf i : unit = u64 buf (Int64.of_int i)
+  let[@inline] int buf i : unit = u64 buf (encode_zigzag (Int64.of_int i))
+end

src/leb128/containers_leb128.mli

@@ -0,0 +1,49 @@
+(** LEB128 encoding and decoding.
+
+    See https://en.wikipedia.org/wiki/LEB128 . *)
+
+module Byte_slice = CCByte_slice
+module Byte_buffer = CCByte_buffer
+
+module Decode : sig
+  val decode_zigzag : int64 -> int64
+  (** Turn an unsigned integer into a signed one.
+
+      See https://en.wikipedia.org/wiki/Variable-length_quantity#Zigzag_encoding
+  *)
+
+  val skip : Byte_slice.t -> int -> int
+  (** [skip slice off] reads an integer at offset [off], and returns how many
+      bytes the integer occupies. *)
+
+  val u64 : Byte_slice.t -> int -> int64 * int
+  (** [u64 slice off] reads an integer at offset [off], and returns a pair
+      [v, n_consumed]. [v] is the read integer, [n_consumed] is the number of
+      bytes consumed during reading. *)
+
+  val i64 : Byte_slice.t -> int -> int64 * int
+  (** Read a signed int64 by reading a u64 and zigzag decoding it *)
+
+  val int_truncate : Byte_slice.t -> int -> int * int
+  (** Like {!i64} but truncates to integer. Returns a pair [v, n_consumed]. *)
+
+  val uint_truncate : Byte_slice.t -> int -> int * int
+  (** Like {!u64} but truncates to integer. *)
+end
+
+module Encode : sig
+  val encode_zigzag : int64 -> int64
+  (** Turn a signed int64 into a u64 via zigzag encoding. *)
+
+  val u64 : Byte_buffer.t -> int64 -> unit
+  (** Write a unsigned int *)
+
+  val i64 : Byte_buffer.t -> int64 -> unit
+  (** Write a signed int via zigzag encoding *)
+
+  val uint : Byte_buffer.t -> int -> unit
+  (** Turn an uint into a u64 and write it *)
+
+  val int : Byte_buffer.t -> int -> unit
+  (** Turn an int into a int64 and write it *)
+end

src/leb128/dune

@@ -0,0 +1,11 @@
+(library
+ (name containers_leb128)
+ (public_name containers.leb128)
+ (synopsis
+  "LEB128 encoding (https://en.wikipedia.org/wiki/LEB128) for cephalopod")
+ (libraries containers)
+ (foreign_stubs
+  (language c)
+  (flags :standard -std=c99 -O2)
+  (names stubs))
+ (ocamlopt_flags :standard -inline 100))

src/leb128/stubs.c

@@ -0,0 +1,73 @@
+
+// readapted from ocaml-protoc, original code also from c-cube
+
+#include <caml/alloc.h>
+#include <caml/memory.h>
+#include <caml/mlvalues.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+static inline int ix_leb128_varint_size(uint64_t i) {
+/* generated with:
+for i in range(1,10):
+  ceiling = (1 << (i*7))-1
+  print(f'if (i <= {ceiling}L) return {i};')
+*/
+
+  if (i <= 127L) return 1;
+  if (i <= 16383L) return 2;
+  if (i <= 2097151L) return 3;
+  if (i <= 268435455L) return 4;
+  if (i <= 34359738367L) return 5;
+  if (i <= 4398046511103L) return 6;
+  if (i <= 562949953421311L) return 7;
+  if (i <= 72057594037927935L) return 8;
+  if (i <= 9223372036854775807L) return 9;
+  return 10;
+}
+
+// number of bytes for i
+CAMLprim value caml_cc_leb128_varint_size(int64_t i) {
+  int res = ix_leb128_varint_size(i);
+  return Val_int(res);
+}
+
+// boxed version, for bytecode
+CAMLprim value caml_cc_leb128_varint_size_byte(value v_i) {
+  CAMLparam1(v_i);
+
+  int64_t i = Int64_val(v_i);
+  int res = ix_leb128_varint_size(i);
+  CAMLreturn(Val_int(res));
+}
+
+// write i at str[idx…] in varint
+static inline void ix_leb128_varint(unsigned char *str, uint64_t i) {
+  while (true) {
+    uint64_t cur = i & 0x7f;
+    if (cur == i) {
+      *str = (unsigned char)cur;
+      break;
+    } else {
+      *str = (unsigned char)(cur | 0x80);
+      i = i >> 7;
+      ++str;
+    }
+  }
+}
+
+// write `i` starting at `idx`
+CAMLprim value caml_cc_leb128_varint(value _str, intnat idx, int64_t i) {
+  unsigned char *str = Bytes_val(_str);
+  ix_leb128_varint(str + idx, i);
+  return Val_unit;
+}
+
+CAMLprim value caml_cc_leb128_varint_byte(value _str, value _idx, value _i) {
+  CAMLparam3(_str, _idx, _i);
+  unsigned char *str = Bytes_val(_str);
+  int idx = Int_val(_idx);
+  int64_t i = Int64_val(_i);
+  ix_leb128_varint(str + idx, i);
+  CAMLreturn(Val_unit);
+}

src/pvec/containers_pvec.ml

@@ -352,6 +352,8 @@ let append a b =
   else
     fold_left push a b
 
+let flat_map f v : _ t = fold_left (fun acc x -> append acc (f x)) empty v
+
 let rec equal_tree eq t1 t2 =
   match t1, t2 with
   | Empty, Empty -> true

src/pvec/containers_pvec.mli

@@ -84,6 +84,11 @@ val append : 'a t -> 'a t -> 'a t
 
 val map : ('a -> 'b) -> 'a t -> 'b t
 
+val flat_map : ('a -> 'b t) -> 'a t -> 'b t
+(** A basic, fairly slow [flat_map] operation like {!CCList.flat_map}.
+    It exists for convenience but is not where this data structure shines.
+    @since 3.17 *)
+
 val choose : 'a t -> 'a option
 (** Return an element. It is unspecified which one is returned. *)
 

tests/core/t_cbor.ml

@@ -99,12 +99,28 @@ let rec shrink (c : Cbor.t) : Cbor.t Q.Iter.t =
     let+ s = Q.Shrink.string s in
     `Bytes s
 
-let arb = Q.make ~shrink ~print:Cbor.to_string_diagnostic gen_c;;
+let arb = Q.make ~shrink ~print:Cbor.to_string_diagnostic gen_c
+
+let rec eq_c c c' =
+  match c, c' with
+  | `Null, `Null | `Undefined, `Undefined -> true
+  | `Simple i, `Simple i' -> Int.equal i i'
+  | `Bool b, `Bool b' -> Bool.equal b b'
+  | `Int i, `Int i' -> Int64.equal i i'
+  | `Float f, `Float f' -> Float.equal f f'
+  | `Bytes s, `Bytes s' -> String.equal s s'
+  | `Text t, `Text t' -> String.equal t t'
+  | `Array a, `Array a' -> CCList.equal eq_c a a'
+  | `Map m, `Map m' ->
+    CCList.equal (fun (t0, t1) (t0', t1') -> eq_c t0 t0' && eq_c t1 t1') m m'
+  | `Tag (i, t), `Tag (i', t') -> Int.equal i i' && eq_c t t'
+  | _ -> false
+;;
 
 q ~count:1_000 ~long_factor:10 arb @@ fun c ->
 let s = Cbor.encode c in
 let c' = Cbor.decode_exn s in
-if not (c = c') then
+if not (eq_c c c') then
   Q.Test.fail_reportf "@[<hv2>roundtrip failed:@ from %a@ to %a@]"
     Cbor.pp_diagnostic c Cbor.pp_diagnostic c';
 true

tests/core/t_char.ml

@@ -8,3 +8,76 @@ eq None (of_int 257);;
 q
   (Q.string_of_size (Q.Gen.return 1))
   (fun s -> Stdlib.( = ) (to_string s.[0]) s)
+;;
+
+q (Q.int_range 65 90 |> Q.map Char.chr) CCChar.is_uppercase_ascii;;
+
+q
+  (Q.int_range 0 64 |> Q.map Char.chr)
+  (fun c -> not @@ CCChar.is_uppercase_ascii c)
+;;
+
+q
+  (Q.int_range 91 127 |> Q.map Char.chr)
+  (fun c -> not @@ CCChar.is_uppercase_ascii c)
+;;
+
+q (Q.int_range 97 122 |> Q.map Char.chr) CCChar.is_lowercase_ascii;;
+
+q
+  (Q.int_range 0 96 |> Q.map Char.chr)
+  (fun c -> not @@ CCChar.is_lowercase_ascii c)
+;;
+
+q
+  (Q.int_range 123 127 |> Q.map Char.chr)
+  (fun c -> not @@ CCChar.is_lowercase_ascii c)
+;;
+
+q (Q.int_range 48 57 |> Q.map Char.chr) CCChar.is_digit_ascii;;
+q (Q.int_range 0 47 |> Q.map Char.chr) (fun c -> not @@ CCChar.is_digit_ascii c)
+;;
+
+q
+  (Q.int_range 58 127 |> Q.map Char.chr)
+  (fun c -> not @@ CCChar.is_digit_ascii c)
+;;
+
+eq true
+  (Stdlib.List.for_all CCChar.is_whitespace_ascii
+     [ '\n'; '\t'; ' '; '\010'; '\011'; '\012'; '\013' ])
+;;
+
+eq false
+  (Stdlib.List.exists CCChar.is_whitespace_ascii
+     [
+       'H';
+       'e';
+       'l';
+       'l';
+       'o';
+       '!';
+       '-';
+       '-';
+       'N';
+       'O';
+       't';
+       'h';
+       'i';
+       'n';
+       'a';
+       '\055';
+       'k';
+       'a';
+       'g';
+       '$';
+       '$';
+       '$';
+       '%';
+       '^';
+       'b';
+       'c';
+       'h';
+       '\008';
+       'h';
+     ])

tests/core/t_fun.ml

@@ -21,3 +21,15 @@ true
 t @@ fun () -> CCFun.((succ %> string_of_int) 2 = "3");;
 t @@ fun () -> CCFun.((( * ) 3 % succ) 5 = 18);;
 t @@ fun () -> CCFun.(succ @@ ( * ) 2 @@ pred @@ 3 = 5)
+
+let find_array arr x =
+  let@ return = with_return in
+  for i = 0 to Array.length arr - 1 do
+    if arr.(i) = x then return i
+  done;
+  -1
+;;
+
+eq 1 @@ find_array [| "a"; "b"; "c" |] "b";;
+eq 2 @@ find_array [| "a"; "b"; "c" |] "c";;
+eq (-1) @@ find_array [| "a"; "b"; "c" |] "hello"

tests/core/t_hash.ml

@@ -11,6 +11,8 @@ t @@ fun () -> char 'c' >= 0;;
 t @@ fun () -> int 152352 = int 152352;;
 t @@ fun () -> list_comm int [ 1; 2 ] = list_comm int [ 2; 1 ];;
 t @@ fun () -> list_comm int [ 1; 2 ] <> list_comm int [ 2; 3 ];;
+t @@ fun () -> string "abcd" >= 0;;
+t @@ fun () -> string "abc" <> string "abcd";;
 
 q Q.int (fun i ->
     Q.assume (i >= 0);

tests/core/t_list.ml

@@ -721,6 +721,13 @@ q
     let i = abs i in
     let l1, l2 = take_drop i l in
     l1 @ l2 = l)
+;;
+
+q
+  (Q.pair (Q.list Q.small_int) Q.int)
+  (fun (l, i) ->
+    let i = abs i in
+    take_drop i l = (take i l, drop i l))
 
 let subs = sublists_of_len;;
 

tests/core/t_string.ml

@@ -229,7 +229,28 @@ t @@ fun () -> not (suffix ~suf:"cd" "abcde");;
 t @@ fun () -> not (suffix ~suf:"abcd" "cd");;
 eq ("ab", "cd") (take_drop 2 "abcd");;
 eq ("abc", "") (take_drop 3 "abc");;
-eq ("abc", "") (take_drop 5 "abc")
+eq ("abc", "") (take_drop 5 "abc");;
+
+q
+  Q.(printable_string)
+  (fun s ->
+    let predicate c = Char.code c mod 2 = 0 in
+    let prefix = take_while predicate s in
+    let suffix = drop_while predicate s in
+    if prefix ^ suffix <> s then
+      Q.Test.fail_reportf "s=%S, pre=%S, post=%S" s prefix suffix;
+    true)
+;;
+
+q
+  Q.(printable_string)
+  (fun s ->
+    let predicate c = Char.code c mod 2 = 0 in
+    let prefix = rdrop_while predicate s in
+    let suffix = rtake_while predicate s in
+    if prefix ^ suffix <> s then
+      Q.Test.fail_reportf "s=%S, pre=%S, post=%S" s prefix suffix;
+    true)
 
 let eq' = eq ~printer:Q.Print.(option string);;
 
@@ -280,6 +301,23 @@ eq ~printer:CCFun.id "" (unlines []);;
 eq ~printer:CCFun.id "ab\nc\n" (unlines [ "ab"; "c" ]);;
 q Q.printable_string (fun s -> trim (unlines (lines s)) = trim s);;
 q Q.printable_string (fun s -> trim (unlines_gen (lines_gen s)) = trim s);;
+eq ~printer:CCFun.id "" (take_while (Char.equal 'c') "heloo_cc");;
+eq ~printer:CCFun.id "" (take_while (Char.equal 'c') "");;
+eq ~printer:CCFun.id "c" (take_while (Char.equal 'c') "c");;
+eq ~printer:CCFun.id "ccc" (take_while (Char.equal 'c') "cccujsuy");;
+
+eq ~printer:CCFun.id "THIS"
+  (take_while (fun c -> Char.code c < 91) "THISisNotWHAtIwANTED")
+;;
+
+eq ~printer:CCFun.id "cc" (rtake_while (Char.equal 'c') "heloo_cc");;
+eq ~printer:CCFun.id "" (rtake_while (Char.equal 'c') "");;
+eq ~printer:CCFun.id "c" (rtake_while (Char.equal 'c') "c");;
+eq ~printer:CCFun.id "" (rtake_while (Char.equal 'c') "cccujsuy");;
+
+eq ~printer:CCFun.id "ANTED"
+  (rtake_while (fun c -> Char.code c < 91) "THISisNotWHAtIwANTED")
+;;
 
 q
   Q.(small_list small_string)

tests/pvec/t_pvec.ml

@@ -119,6 +119,8 @@ module Ref_impl = struct
   let to_list l = l
   let to_seq = CCSeq.of_list
   let add_list l l2 : _ t = List.append l l2
+  let append self l2 : _ t = List.append self l2
+  let flat_map sub l : _ t = CCList.flat_map (fun x -> sub @ [ x ]) l
 
   let to_list_via_reviter m =
     let l = ref [] in
@@ -159,7 +161,9 @@ module Op = struct
     | Push of 'a
     | Pop
     (* TODO: set *)
+    | Append of 'a list
     | Add_list of 'a list
+    | Flat_map of 'a list
     | Check_get of int
     | Check_choose
     | Check_is_empty
@@ -176,6 +180,8 @@ module Op = struct
       | Push _ :: tl -> loop (size + 1) tl
       | Pop :: tl -> size >= 0 && loop (size - 1) tl
       | Add_list l :: tl -> loop (size + List.length l) tl
+      | Append l :: tl -> loop (size + List.length l) tl
+      | Flat_map sub :: tl -> loop (size * (1 + List.length sub)) tl
       | Check_get x :: tl -> x < size && loop size tl
       | Check_choose :: tl
       | Check_is_empty :: tl
@@ -194,6 +200,8 @@ module Op = struct
     | Push x -> spf "push %s" (show_x x)
     | Pop -> "pop"
     | Add_list l -> spf "add_list [%s]" (String.concat ";" @@ List.map show_x l)
+    | Append l -> spf "append [%s]" (String.concat ";" @@ List.map show_x l)
+    | Flat_map l -> spf "flat_map [%s]" (String.concat ";" @@ List.map show_x l)
     | Check_get i -> spf "check_get %d" i
     | Check_choose -> "check_choose"
     | Check_is_empty -> "check_is_empty"
@@ -211,6 +219,8 @@ module Op = struct
     | Push x -> shrink_x x >|= fun x -> Push x
     | Pop -> empty
     | Add_list l -> list ~shrink:shrink_x l >|= fun x -> Add_list x
+    | Append l -> list ~shrink:shrink_x l >|= fun x -> Append x
+    | Flat_map l -> list ~shrink:shrink_x l >|= fun x -> Flat_map x
     | Check_get _ | Check_choose | Check_is_empty | Check_len | Check_to_list
     | Check_to_gen | Check_last | Check_rev_iter | Check_iter ->
       empty
@@ -252,6 +262,12 @@ module Op = struct
                    ( 1,
                      small_list gen_x >|= fun l ->
                      Add_list l, size + List.length l );
+                   ( 1,
+                     small_list gen_x >|= fun l ->
+                     Append l, size + List.length l );
+                   ( 1,
+                     list_size (0 -- 5) gen_x >|= fun l ->
+                     Flat_map l, size * (1 + List.length l) );
                  ];
                ]
         in
@@ -292,6 +308,12 @@ let check_ops ~show_x (ops : 'a Op.t list) : unit =
       | Op.Add_list l ->
         cur := add_list !cur l;
         cur_ref := Ref_impl.add_list !cur_ref l
+      | Op.Append l ->
+        cur := append !cur (of_list l);
+        cur_ref := Ref_impl.append !cur_ref l
+      | Op.Flat_map sub ->
+        cur := flat_map (fun x -> push (of_list sub) x) !cur;
+        cur_ref := Ref_impl.flat_map sub !cur_ref
       | Op.Check_get i -> if get !cur i <> Ref_impl.get i !cur_ref then fail ()
       | Op.Check_is_empty ->
         if is_empty !cur <> Ref_impl.is_empty !cur_ref then fail ()