feat: add infix operators to String

close #315

src/core/CCString.ml

@@ -3,6 +3,10 @@
 
 (** {1 Basic String Utils} *)
 
+(*$inject
+  open CCShims_.Stdlib
+*)
+
 open CCShims_
 
 type 'a iter = ('a -> unit) -> unit
@@ -1053,6 +1057,22 @@ let pp_buf buf s =
 let pp fmt s =
   Format.fprintf fmt "\"%s\"" s
 
+module Infix = struct
+  let (=) = equal
+  let (<>) a b = not (equal a b)
+  let (>) : t -> t -> bool = CCShims_.Stdlib.(>)
+  let (>=) : t -> t -> bool = CCShims_.Stdlib.(>=)
+  let (<) : t -> t -> bool = CCShims_.Stdlib.(<)
+  let (<=) : t -> t -> bool = CCShims_.Stdlib.(<=)
+end
+
+include Infix
+
+(*$T
+  "ab" < "abc"
+  "123" < "14"
+ *)
+
 (* test consistency of interfaces *)
 (*$inject
   module type L = module type of CCString

src/core/CCString.mli

@@ -417,3 +417,29 @@ val edit_distance : ?cutoff:int -> string -> string -> int
       and on the result. (since 3.0). This is useful if you just want to
     check whether the edit distance is less or equal than 2 (use cutoff of 3).
 *)
+
+(** {2 Infix operators}
+
+    @since NEXT_RELEASE *)
+
+module Infix : sig
+  val (=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<>) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (>=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (>) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+end
+
+include module type of Infix

src/core/CCStringLabels.mli

@@ -436,3 +436,29 @@ val edit_distance : ?cutoff:int -> string -> string -> int
       and on the result. (since 3.0). This is useful if you just want to
     check whether the edit distance is less or equal than 2 (use cutoff of 3).
 *)
+
+(** {2 Infix operators}
+
+    @since NEXT_RELEASE *)
+
+module Infix : sig
+  val (=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<>) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (<=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (>=) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+
+  val (>) : t -> t -> bool
+  (** @since NEXT_RELEASE *)
+end
+
+include module type of Infix