20 files changed, 51 insertions, 0 deletions

diff --git a/Changes b/Changes
index 2a030d365d..69157e5e1b 100644
--- a/Changes
+++ b/Changes
@@ -29,6 +29,9 @@ Runtime system:
   (Xavier Leroy)
 
 Standard library:
+* PR#6494: Add equal function in modules
+  Big_int, Bytes, Char, Digest, Int32, Int64, Nativeint, Num and String
+  (Romain Calascibetta)
 - PR#6577: improve performance of %L, %l, %n, %S, %C format specifiers
   (Alain Frisch)
 - PR#6585: fix memory leak in win32unix/createprocess.c
diff --git a/otherlibs/num/big_int.ml b/otherlibs/num/big_int.ml
index 847d158324..36e40f4dd4 100644
--- a/otherlibs/num/big_int.ml
+++ b/otherlibs/num/big_int.ml
@@ -70,6 +70,8 @@ let compare_big_int bi1 bi2 =
             compare_nat (bi2.abs_value) 0 (num_digits_big_int bi2)
                         (bi1.abs_value) 0 (num_digits_big_int bi1)
 
+let equal bi1 bi2 = compare_big_int bi1 bi2 = 0
+
 let eq_big_int bi1 bi2 = compare_big_int bi1 bi2 = 0
 and le_big_int bi1 bi2 = compare_big_int bi1 bi2 <= 0
 and ge_big_int bi1 bi2 = compare_big_int bi1 bi2 >= 0
diff --git a/otherlibs/num/big_int.mli b/otherlibs/num/big_int.mli
index 738730a79a..09f4514203 100644
--- a/otherlibs/num/big_int.mli
+++ b/otherlibs/num/big_int.mli
@@ -86,6 +86,8 @@ val compare_big_int : big_int -> big_int -> int
         (** [compare_big_int a b] returns [0] if [a] and [b] are equal,
            [1] if [a] is greater than [b], and [-1] if [a] is smaller
            than [b]. *)
+val equal : big_int -> big_int -> bool
+        (** The equal function for big ints. @since 4.03.0 *)
 val eq_big_int : big_int -> big_int -> bool
 val le_big_int : big_int -> big_int -> bool
 val ge_big_int : big_int -> big_int -> bool
diff --git a/otherlibs/num/num.ml b/otherlibs/num/num.ml
index 67499e2674..67cc16c0b6 100644
--- a/otherlibs/num/num.ml
+++ b/otherlibs/num/num.ml
@@ -330,6 +330,8 @@ and le_num num1 num2 = compare_num num1 num2 <= 0
 and gt_num num1 num2 = compare_num num1 num2 > 0
 and ge_num num1 num2 = compare_num num1 num2 >= 0
 
+let equal a b = compare_num a b = 0
+
 let ( </ ) = lt_num
 and ( <=/ ) = le_num
 and ( >/ ) = gt_num
diff --git a/otherlibs/num/num.mli b/otherlibs/num/num.mli
index 6425085e63..a43929ef2b 100644
--- a/otherlibs/num/num.mli
+++ b/otherlibs/num/num.mli
@@ -129,6 +129,10 @@ val compare_num : num -> num -> int
 (** Return [-1], [0] or [1] if the first argument is less than,
    equal to, or greater than the second argument. *)
 
+val equal : num -> num -> bool
+(** The equal function for nums.
+    @since 4.03.0 *)
+
 val max_num : num -> num -> num
 (** Return the greater of the two arguments. *)
 
diff --git a/stdlib/bytes.ml b/stdlib/bytes.ml
index ce6e126db8..4170ad02e5 100644
--- a/stdlib/bytes.ml
+++ b/stdlib/bytes.ml
@@ -260,3 +260,4 @@ let rcontains_from s i c =
 type t = bytes
 
 let compare (x: t) (y: t) = Pervasives.compare x y
+external equal : t -> t -> bool = "caml_string_equal"
diff --git a/stdlib/bytes.mli b/stdlib/bytes.mli
index 82b28a28c5..e873463a1f 100644
--- a/stdlib/bytes.mli
+++ b/stdlib/bytes.mli
@@ -255,6 +255,9 @@ val compare: t -> t -> int
     this function [compare] allows the module [Bytes] to be passed as
     argument to the functors {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equality function for byte sequences.
+    @since 4.03.0 *)
 
 (** {4 Unsafe conversions (for advanced users)}
 
diff --git a/stdlib/char.ml b/stdlib/char.ml
index 15c4635429..1ba5bf6ff9 100644
--- a/stdlib/char.ml
+++ b/stdlib/char.ml
@@ -65,3 +65,4 @@ let uppercase c =
 type t = char
 
 let compare c1 c2 = code c1 - code c2
+let equal (c1: t) (c2: t) = compare c1 c2 = 0
diff --git a/stdlib/char.mli b/stdlib/char.mli
index d1baa64d3f..0ff4efb082 100644
--- a/stdlib/char.mli
+++ b/stdlib/char.mli
@@ -41,6 +41,10 @@ val compare: t -> t -> int
     allows the module [Char] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for chars.
+    @since 4.03.0 *)
+
 (**/**)
 
 (* The following is for system use only. Do not call directly. *)
diff --git a/stdlib/digest.ml b/stdlib/digest.ml
index 14cb4ebd90..4261564ffe 100644
--- a/stdlib/digest.ml
+++ b/stdlib/digest.ml
@@ -16,6 +16,7 @@
 type t = string
 
 let compare = String.compare
+let equal = String.equal
 
 external unsafe_string: string -> int -> int -> t = "caml_md5_string"
 external channel: in_channel -> int -> t = "caml_md5_chan"
diff --git a/stdlib/digest.mli b/stdlib/digest.mli
index 9227cd7de8..29e5b3973e 100644
--- a/stdlib/digest.mli
+++ b/stdlib/digest.mli
@@ -33,6 +33,10 @@ val compare : t -> t -> int
     argument to the functors {!Set.Make} and {!Map.Make}.
     @since 4.00.0 *)
 
+val equal : t -> t -> bool
+(** The equal function for 16-character digest.
+    @since 4.03.0 *)
+
 val string : string -> t
 (** Return the digest of the given string. *)
 
diff --git a/stdlib/int32.ml b/stdlib/int32.ml
index e8e55ddc84..63c99e3d42 100644
--- a/stdlib/int32.ml
+++ b/stdlib/int32.ml
@@ -50,3 +50,4 @@ external of_string : string -> int32 = "caml_int32_of_string"
 type t = int32
 
 let compare (x: t) (y: t) = Pervasives.compare x y
+let equal (x: t) (y: t) = compare x y = 0
diff --git a/stdlib/int32.mli b/stdlib/int32.mli
index fcd300a2d5..4a29e6c0f2 100644
--- a/stdlib/int32.mli
+++ b/stdlib/int32.mli
@@ -153,6 +153,10 @@ val compare: t -> t -> int
     allows the module [Int32] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for int32s.
+    @since 4.03.0 *)
+
 (**/**)
 
 (** {6 Deprecated functions} *)
diff --git a/stdlib/int64.ml b/stdlib/int64.ml
index aa4add5f1b..274a9868d9 100644
--- a/stdlib/int64.ml
+++ b/stdlib/int64.ml
@@ -55,3 +55,4 @@ external float_of_bits : int64 -> float = "caml_int64_float_of_bits"
 type t = int64
 
 let compare (x: t) (y: t) = Pervasives.compare x y
+let equal (x: t) (y: t) = compare x y = 0
diff --git a/stdlib/int64.mli b/stdlib/int64.mli
index 09b476f15a..edd600c690 100644
--- a/stdlib/int64.mli
+++ b/stdlib/int64.mli
@@ -175,6 +175,10 @@ val compare: t -> t -> int
     allows the module [Int64] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for int64s.
+    @since 4.03.0 *)
+
 (**/**)
 
 (** {6 Deprecated functions} *)
diff --git a/stdlib/nativeint.ml b/stdlib/nativeint.ml
index 94c4b94901..7412bca04e 100644
--- a/stdlib/nativeint.ml
+++ b/stdlib/nativeint.ml
@@ -51,3 +51,4 @@ external of_string: string -> nativeint = "caml_nativeint_of_string"
 type t = nativeint
 
 let compare (x: t) (y: t) = Pervasives.compare x y
+let equal (x: t) (y: t) = compare x y = 0
diff --git a/stdlib/nativeint.mli b/stdlib/nativeint.mli
index 3dce1b6c49..ffa57030cd 100644
--- a/stdlib/nativeint.mli
+++ b/stdlib/nativeint.mli
@@ -171,6 +171,10 @@ val compare: t -> t -> int
     allows the module [Nativeint] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for natives ints.
+    @since 4.03.0 *)
+
 (**/**)
 
 (** {6 Deprecated functions} *)
diff --git a/stdlib/string.ml b/stdlib/string.ml
index 93880af268..8b2dde65d6 100644
--- a/stdlib/string.ml
+++ b/stdlib/string.ml
@@ -124,3 +124,4 @@ let uncapitalize s =
 type t = string
 
 let compare (x: t) (y: t) = Pervasives.compare x y
+external equal : string -> string -> bool = "caml_string_equal"
diff --git a/stdlib/string.mli b/stdlib/string.mli
index 56065bbfbd..e063e6bdba 100644
--- a/stdlib/string.mli
+++ b/stdlib/string.mli
@@ -239,6 +239,10 @@ val compare: t -> t -> int
     allows the module [String] to be passed as argument to the functors
     {!Set.Make} and {!Map.Make}. *)
 
+val equal: t -> t -> bool
+(** The equal function for strings.
+    @since 4.03.0 *)
+
 (**/**)
 
 (* The following is for system use only. Do not call directly. *)
diff --git a/testsuite/tests/typing-modules/aliases.ml.reference b/testsuite/tests/typing-modules/aliases.ml.reference
index db35fa5e86..6469844b49 100644
--- a/testsuite/tests/typing-modules/aliases.ml.reference
+++ b/testsuite/tests/typing-modules/aliases.ml.reference
@@ -10,6 +10,7 @@
     val uppercase : char -> char
     type t = char
     val compare : t -> t -> int
+    val equal : t -> t -> bool
     external unsafe_chr : int -> char = "%identity"
   end
 # - : char = 'B'
@@ -22,6 +23,7 @@
     val uppercase : char -> char
     type t = char
     val compare : t -> t -> int
+    val equal : t -> t -> bool
     external unsafe_chr : int -> char = "%identity"
   end
 # - : char = 'B'
@@ -37,6 +39,7 @@
       val uppercase : char -> char
       type t = char
       val compare : t -> t -> int
+      val equal : t -> t -> bool
       external unsafe_chr : int -> char = "%identity"
     end
 # module C4 :
@@ -48,6 +51,7 @@
     val uppercase : char -> char
     type t = char
     val compare : t -> t -> int
+    val equal : t -> t -> bool
     external unsafe_chr : int -> char = "%identity"
   end
 # - : char = 'B'