melange-ppx: deprecate [@@mel.val] and suggest its removal (#678)

* melange-ppx: deprecate `[@@mel.val]` and suggest its removal

* chore: remove `mel.val` attribute from runtime/stdlib

* chore: add changelog entry

* chore: promote tests

Changes.md

@@ -45,6 +45,10 @@ Unreleased
   [#664](https://github.com/melange-re/melange/pull/664))
 - [melange]: Upgrade the OCaml typechecker version to 5.1
   ([#668](https://github.com/melange-re/melange/pull/668))
+- [melange.ppx]: Deprecate `[@@mel.val]` and suggest its removal. This
+  attribute is redundant and unnecessary
+  ([#675](https://github.com/melange-re/melange/issues/675),
+  [#678](https://github.com/melange-re/melange/pull/678))
 
 1.0.0 2023-05-31
 ---------------

jscomp/others/belt_Float.ml

@@ -26,15 +26,15 @@
     Utililites for Float
 *)
 
-external isNaN : float -> bool = "isNaN" [@@mel.val]
+external isNaN : float -> bool = "isNaN"
 external toInt : float -> int = "%intoffloat"
 external fromInt : int -> float = "%identity"
-external fromString : string -> float = "parseFloat" [@@mel.val]
+external fromString : string -> float = "parseFloat"
 
 let fromString i =
   match fromString i with i when isNaN i -> None | i -> Some i
 
-external toString : float -> string = "String" [@@mel.val]
+external toString : float -> string = "String"
 external ( + ) : float -> float -> float = "%addfloat"
 external ( - ) : float -> float -> float = "%subfloat"
 external ( * ) : float -> float -> float = "%mulfloat"

jscomp/others/belt_Float.mli

@@ -29,7 +29,7 @@
 external toInt : float -> int = "%intoffloat"
 external fromInt : int -> float = "%identity"
 val fromString : string -> float option
-external toString : float -> string = "String" [@@mel.val]
+external toString : float -> string = "String"
 external ( + ) : float -> float -> float = "%addfloat"
 external ( - ) : float -> float -> float = "%subfloat"
 external ( * ) : float -> float -> float = "%mulfloat"

jscomp/others/belt_Int.ml

@@ -26,15 +26,15 @@
     Utililites for Int
 *)
 
-external isNaN : int -> bool = "isNaN" [@@mel.val]
+external isNaN : int -> bool = "isNaN"
 external toFloat : int -> float = "%identity"
 external fromFloat : float -> int = "%intoffloat"
-external fromString : string -> (_[@mel.as 10]) -> int = "parseInt" [@@mel.val]
+external fromString : string -> (_[@mel.as 10]) -> int = "parseInt"
 
 let fromString i =
   match fromString i with i when isNaN i -> None | i -> Some i
 
-external toString : int -> string = "String" [@@mel.val]
+external toString : int -> string = "String"
 external ( + ) : int -> int -> int = "%addint"
 external ( - ) : int -> int -> int = "%subint"
 external ( * ) : int -> int -> int = "%mulint"

jscomp/others/belt_Int.mli

@@ -29,7 +29,7 @@
 external toFloat : int -> float = "%identity"
 external fromFloat : float -> int = "%intoffloat"
 val fromString : string -> int option
-external toString : int -> string = "String" [@@mel.val]
+external toString : int -> string = "String"
 external ( + ) : int -> int -> int = "%addint"
 external ( - ) : int -> int -> int = "%subint"
 external ( * ) : int -> int -> int = "%mulint"

jscomp/others/dom_storage.ml

@@ -1,15 +1,15 @@
 type t = Dom_storage2.t
 
 external getItem : string -> string option = "getItem"
-  [@@mel.send.pipe: t] [@@mel.return null_to_opt]
+[@@mel.send.pipe: t] [@@mel.return null_to_opt]
 
 external setItem : string -> string -> unit = "setItem" [@@mel.send.pipe: t]
 external removeItem : string -> unit = "removeItem" [@@mel.send.pipe: t]
 external clear : unit = "clear" [@@mel.send.pipe: t]
 
 external key : int -> string option = "key"
-  [@@mel.send.pipe: t] [@@mel.return null_to_opt]
+[@@mel.send.pipe: t] [@@mel.return null_to_opt]
 
 external length : t -> int = "length" [@@mel.get]
-external localStorage : t = "localStorage" [@@mel.val]
-external sessionStorage : t = "sessionStorage" [@@mel.val]
+external localStorage : t = "localStorage"
+external sessionStorage : t = "sessionStorage"

jscomp/others/dom_storage2.ml

@@ -1,15 +1,15 @@
 type t
 
 external getItem : t -> string -> string option = "getItem"
-  [@@mel.send] [@@mel.return null_to_opt]
+[@@mel.send] [@@mel.return null_to_opt]
 
 external setItem : t -> string -> string -> unit = "setItem" [@@mel.send]
 external removeItem : t -> string -> unit = "removeItem" [@@mel.send]
 external clear : t -> unit = "clear" [@@mel.send]
 
 external key : t -> int -> string option = "key"
-  [@@mel.send] [@@mel.return null_to_opt]
+[@@mel.send] [@@mel.return null_to_opt]
 
 external length : t -> int = "length" [@@mel.get]
-external localStorage : t = "localStorage" [@@mel.val]
-external sessionStorage : t = "sessionStorage" [@@mel.val]
+external localStorage : t = "localStorage"
+external sessionStorage : t = "sessionStorage"

jscomp/others/node_buffer.ml

@@ -26,18 +26,18 @@
 
 type t = Node.buffer
 
-external isBuffer : 'a -> bool = "Buffer.isBuffer" [@@mel.val]
-external fromString : string -> t = "Buffer.from" [@@mel.val]
+external isBuffer : 'a -> bool = "Buffer.isBuffer"
+external fromString : string -> t = "Buffer.from"
 
 type encoding =
   [ `ascii | `utf8 | `utf16le | `usc2 | `base64 | `latin1 | `binary | `hex ]
 
 external fromStringWithEncoding : string -> encoding -> t = "from"
-  [@@mel.val] [@@mel.scope "Buffer"]
+[@@mel.scope "Buffer"]
 
 external toString : t -> string = "toString" [@@mel.send]
 
 external toStringWithEncoding : t -> encoding -> string = "toString"
-  [@@mel.send]
+[@@mel.send]
 
-external concat : t array -> t = "Buffer.concat" [@@mel.val]
+external concat : t array -> t = "Buffer.concat"

jscomp/others/node_fs.ml

@@ -28,14 +28,14 @@
 *)
 
 external readdirSync : string -> string array = "readdirSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 (** Most fs functions let you omit the callback argument. If you do, a default
     callback is used that rethrows errors. To get a trace to the original call
     site, set the `NODE_DEBUG` environment variable:
 *)
 
 external renameSync : string -> string -> unit = "renameSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 type fd = private int
 
@@ -55,10 +55,10 @@ module Watch = struct
     ?encoding:Js.String.t ->
     unit ->
     config = ""
-    [@@mel.obj]
+  [@@mel.obj]
 
   external watch : string -> ?config:config -> unit -> t = "watch"
-    [@@mel.module "fs"]
+  [@@mel.module "fs"]
   (** there is no need to accept listener, since we return a [watcher]
       back it can register event listener there .
       Currently we introduce a type [string_buffer], for the
@@ -73,7 +73,7 @@ module Watch = struct
      | `error of (unit -> unit[@u]) ]
     [@mel.string]) ->
     t = "on"
-    [@@mel.send.pipe: t] [@@deprecated "Please use `Node.Fs.on_` instead "]
+  [@@mel.send.pipe: t] [@@deprecated "Please use `Node.Fs.on_` instead "]
 
   external on_ :
     t ->
@@ -82,21 +82,21 @@ module Watch = struct
      | `error of (unit -> unit[@u]) ]
     [@mel.string]) ->
     t = "on"
-    [@@mel.send]
+  [@@mel.send]
 
   external close : t -> unit = "close" [@@mel.send]
 end
 
 external ftruncateSync : fd -> int -> unit = "ftruncateSync" [@@mel.module "fs"]
 
 external truncateSync : string -> int -> unit = "truncateSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 external chownSync : string -> uid:int -> gid:int -> unit = "chownSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 external fchownSync : fd -> uid:int -> gid:int -> unit = "fchownSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 external readlinkSync : string -> string = "readlinkSync" [@@mel.module "fs"]
 external unlinkSync : string -> unit = "unlinkSync" [@@mel.module "fs"]
@@ -118,7 +118,7 @@ external openSync :
    | `Append_read_fail_if_exists [@mel.as "ax+"] ]
   [@mel.string]) ->
   unit = "openSync"
-  [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 type encoding =
   [ `hex
@@ -132,18 +132,17 @@ type encoding =
   | `utf16le ]
 
 external readFileSync : string -> encoding -> string = "readFileSync"
-  [@@mel.val] [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 external readFileAsUtf8Sync : string -> (_[@mel.as "utf8"]) -> string
   = "readFileSync"
-  [@@mel.val] [@@mel.module "fs"]
+[@@mel.module "fs"]
 
-external existsSync : string -> bool = "existsSync"
-  [@@mel.val] [@@mel.module "fs"]
+external existsSync : string -> bool = "existsSync" [@@mel.module "fs"]
 
 external writeFileSync : string -> string -> encoding -> unit = "writeFileSync"
-  [@@mel.val] [@@mel.module "fs"]
+[@@mel.module "fs"]
 
 external writeFileAsUtf8Sync : string -> string -> (_[@mel.as "utf8"]) -> unit
   = "writeFileSync"
-  [@@mel.val] [@@mel.module "fs"]
+[@@mel.module "fs"]

jscomp/others/node_module.ml

@@ -25,4 +25,3 @@
 (** Node Module API *)
 
 external module_ : < __cache : Node.node_module Js.Dict.t > Js.t = "module"
-  [@@mel.val]

jscomp/runtime/caml_float.ml

@@ -25,14 +25,14 @@
 open Melange_mini_stdlib
 
 (* borrowed from others/js_math.ml *)
-external _LOG2E : float = "Math.LOG2E" [@@mel.val]
-external _LOG10E : float = "Math.LOG10E" [@@mel.val]
-external abs_float : float -> float = "Math.abs" [@@mel.val]
-external floor : float -> float = "Math.floor" [@@mel.val]
-external exp : float -> float = "exp" [@@mel.val] [@@mel.scope "Math"]
-external log : float -> float = "Math.log" [@@mel.val]
-external sqrt : float -> float = "sqrt" [@@mel.val] [@@mel.scope "Math"]
-external pow_float : base:float -> exp:float -> float = "Math.pow" [@@mel.val]
+external _LOG2E : float = "Math.LOG2E"
+external _LOG10E : float = "Math.LOG10E"
+external abs_float : float -> float = "Math.abs"
+external floor : float -> float = "Math.floor"
+external exp : float -> float = "exp" [@@mel.scope "Math"]
+external log : float -> float = "Math.log"
+external sqrt : float -> float = "sqrt" [@@mel.scope "Math"]
+external pow_float : base:float -> exp:float -> float = "Math.pow"
 external int_of_float : float -> int = "%intoffloat"
 external float_of_int : int -> float = "%floatofint"
 

jscomp/runtime/caml_float.mli

@@ -22,7 +22,7 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)
 
-external floor : float -> float = "Math.floor" [@@mel.val]
+external floor : float -> float = "Math.floor"
 (** *)
 
 external int_of_float : float -> int = "%intoffloat"

jscomp/runtime/caml_float_extern.ml

@@ -1,14 +1,14 @@
-external _NaN : float = "NaN" [@@mel.val]
-external isNaN : float -> bool = "isNaN" [@@mel.val]
-external isFinite : float -> bool = "isFinite" [@@mel.val]
+external _NaN : float = "NaN"
+external isNaN : float -> bool = "isNaN"
+external isFinite : float -> bool = "isFinite"
 
 external toExponentialWithPrecision : float -> digits:int -> string
   = "toExponential"
-  [@@mel.send]
+[@@mel.send]
 
 external toFixed : float -> string = "toFixed" [@@mel.send]
 
 external toFixedWithPrecision : float -> digits:int -> string = "toFixed"
-  [@@mel.send]
+[@@mel.send]
 
-external fromString : string -> float = "Number" [@@mel.val]
+external fromString : string -> float = "Number"

jscomp/runtime/caml_int64.ml

@@ -223,11 +223,11 @@ let rec of_float (x : float) : t =
       ~lo:(Caml_nativeint_extern.of_float (mod_float x two_ptr_32_dbl))
       ~hi:(Caml_nativeint_extern.of_float (x /. two_ptr_32_dbl))
 
-external log2 : float = "LN2" [@@mel.val] [@@mel.scope "Math"]
-external log : float -> float = "log" [@@mel.val] [@@mel.scope "Math"]
-external ceil : float -> float = "ceil" [@@mel.val] [@@mel.scope "Math"]
-external floor : float -> float = "floor" [@@mel.val] [@@mel.scope "Math"]
-(* external maxFloat : float -> float -> float = "Math.max" [@@mel.val] *)
+external log2 : float = "LN2" [@@mel.scope "Math"]
+external log : float -> float = "log" [@@mel.scope "Math"]
+external ceil : float -> float = "ceil" [@@mel.scope "Math"]
+external floor : float -> float = "floor" [@@mel.scope "Math"]
+(* external maxFloat : float -> float -> float = "Math.max"  *)
 
 (* either top 11 bits are all 0 or all 1
    when it is all 1, we need exclude -2^53
@@ -237,7 +237,7 @@ let isSafeInteger { hi; lo } =
   top11Bits = 0
   || (top11Bits = -1 && Pervasives.not (lo = 0 && hi = 0xff_e0_00_00))
 
-external string_of_float : float -> string = "String" [@@mel.val]
+external string_of_float : float -> string = "String"
 
 let rec to_string (self : int64) =
   let ({ hi = self_hi; _ } as self) = unsafe_of_int64 self in

jscomp/runtime/caml_nativeint_extern.ml

@@ -5,4 +5,4 @@ external shift_right_logical : int -> int -> int = "nativeint_lsr"
 external mul : int -> int -> int = "nativeint_mul"
 external to_float : int -> float = "%identity"
 external of_float : float -> int = "caml_int_of_float"
-external to_string : int -> string = "String" [@@mel.val]
+external to_string : int -> string = "String"

jscomp/runtime/caml_obj.ml

@@ -27,7 +27,7 @@ open Melange_mini_stdlib
 type t = Obj.t
 
 module O = struct
-  external isArray : 'a -> bool = "Array.isArray" [@@mel.val]
+  external isArray : 'a -> bool = "Array.isArray"
 
   type key = string
 
@@ -38,7 +38,7 @@ module O = struct
       |}]
 
   external hasOwnProperty : t -> key -> bool = "call"
-    [@@mel.scope "Object", "prototype", "hasOwnProperty"] [@@mel.val]
+  [@@mel.scope "Object", "prototype", "hasOwnProperty"]
   (**
      JS objects are not guaranteed to have `Object` in their prototype
      chain so calling `some_obj.hasOwnProperty(key)` can sometimes throw
@@ -369,7 +369,7 @@ let caml_equal_nullable (x : Obj.t) (y : Obj.t Js_internal.nullable) =
 
 let isNumberOrBigInt a =
   Js_internal.typeof a = "number" || Js_internal.typeof a = "bigint"
-  [@@inline]
+[@@inline]
 
 let canNumericCompare a b = isNumberOrBigInt a && isNumberOrBigInt b [@@inline]