Oct 12, 2025 · Oct 12, 2025 · Oct 12, 2025 · Oct 13, 2025 · Oct 13, 2025 · Oct 13, 2025
diff --git a/Makefile b/Makefile
 cargo build --manifest-path rewatch/Cargo.toml --release
 ./scripts/copyExes.js --rewatch

 # Generate EmbedLang JSON/OpenAPI schemas into docs/schemas
 schemas: rewatch
 @mkdir -p docs/schemas
 @rewatch/target/release/rescript schema embeds --output-dir docs/schemas --openapi >/dev/null
 @echo "Schemas written to docs/schemas"

 ninja/ninja:
 ./scripts/buildNinjaBinary.js


 .DEFAULT_GOAL := build

 .PHONY: build watch rewatch ninja bench dce test test-syntax test-syntax-roundtrip test-gentype test-analysis test-tools test-all lib playground playground-cmijs playground-release artifacts format checkformat clean-gentype clean-rewatch clean clean-all dev-container
 .PHONY: build watch rewatch ninja bench dce test test-syntax test-syntax-roundtrip test-gentype test-analysis test-tools test-all lib playground playground-cmijs playground-release artifacts format checkformat clean-gentype clean-rewatch clean clean-all dev-container schemas
diff --git a/compiler/bsc/rescript_compiler_main.ml b/compiler/bsc/rescript_compiler_main.ml
    ("-dparsetree", set Clflags.dump_parsetree, "*internal* debug parsetree");
    ("-drawlambda", set Clflags.dump_rawlambda, "*internal* debug raw lambda");
    ("-dsource", set Clflags.dump_source, "*internal* print source");
    ( "-embeds",
      string_call (fun s ->
          Js_config.collect_embeds := true;
          let s = String.trim s in
          Js_config.embed_tags :=
            Ext_string.split_by ~keep_empty:false (fun c -> c = ',') s
            |> List.map String.trim),
      "*internal* Collect embed extension occurrences (csv of tags)" );
    (* single-pass embed rewrite via PPX; no separate -rewrite-embeds entry *)
    ( "-reprint-source",
      string_call reprint_source_file,
      "*internal* transform the target ReScript file using PPXes provided, and \
diff --git a/compiler/common/js_config.ml b/compiler/common/js_config.ml
  | module_name -> Generic {module_name}

 let as_pp = ref false

 (* Embed indexing and rewrite configuration *)
 let collect_embeds = ref false
 let embed_tags : string list ref = ref []

 let self_stack : string Stack.t = Stack.create ()
diff --git a/compiler/common/js_config.mli b/compiler/common/js_config.mli

 val as_pp : bool ref

 (* Embed indexing and rewrite configuration *)
 val collect_embeds : bool ref
 (** When true, emit per-module embed index artifacts during parse *)

 val embed_tags : string list ref
 (** Comma-separated list of tags to collect *)

 val self_stack : string Stack.t
diff --git a/compiler/core/js_implementation.ml b/compiler/core/js_implementation.ml
    | Some x -> x
  in
  Res_compmisc.init_path ();
  parser fname
  let ast0 = parser fname in
  (* Emit embed index (if enabled) alongside binary AST output prefix *)
  (try
     Embed_index.write_structure_index ~outprefix:outputprefix ~sourcefile:fname
       ast0
   with _ -> ());
  ast0
  |> Cmd_ppx_apply.apply_rewriters ~restore:false ~tool_name:Js_config.tool_name
       Ml
  |> Ppx_entry.rewrite_implementation
diff --git a/compiler/ext/ext_embed.ml b/compiler/ext/ext_embed.ml
 let get_embed_tag (name : string) : string option =
  let prefix = "embed." in
  let plen = String.length prefix in
  if String.length name > plen && String.sub name 0 plen = prefix then
    Some (String.sub name plen (String.length name - plen))
  else None

 let is_valid_embed_id (s : string) : bool =
  let len = String.length s in
  if len = 0 then false
  else
    let lead = s.[0] in
    let is_letter = function
      | 'A' .. 'Z' | 'a' .. 'z' -> true
      | _ -> false
    in
    let is_ident_char = function
      | 'A' .. 'Z' | 'a' .. 'z' | '0' .. '9' | '_' -> true
      | _ -> false
    in
    if not (is_letter lead) then false
    else
      let rec loop i =
        if i >= len then true
        else if is_ident_char s.[i] then loop (i + 1)
        else false
      in
      loop 1

 let invalid_id_error_message =
  "Invalid `id` for embed. Embed `id` must start with a letter, and only \
   contain letters, digits, and underscores."

 let missing_id_error_message = "Embed config record must include `id: string`."

 let invalid_payload_error_message =
  "Embed payload must be either a string literal or a record literal."

 let normalize_tag_for_symbol (tag : string) : string =
  (* Embed tags are already validated by the parser as extension identifiers
     (attr-id with optional dot-separated segments). We only need to make the
     tag segment safe for inclusion in a single identifier by mapping '.' to
     '_'. *)
  let b = Bytes.of_string tag in
  for i = 0 to Bytes.length b - 1 do
    if Bytes.get b i = '.' then Bytes.set b i '_'
  done;
  Bytes.unsafe_to_string b
diff --git a/compiler/ext/ext_embed.mli b/compiler/ext/ext_embed.mli
 val get_embed_tag : string -> string option
 (** [get_embed_tag name] returns [Some base] when [name] starts with
    the embed prefix "embed." and has a non-empty remainder; otherwise [None]. *)

 val is_valid_embed_id : string -> bool
 (** Validate embed `id`: must start with a letter and contain only
    letters, digits, and underscores. *)

 val invalid_id_error_message : string
 (** Centralized error message for invalid embed `id`. *)

 val missing_id_error_message : string
 (** Error when a config record omits `id` or provides a non-string `id`. *)

 val invalid_payload_error_message : string
 (** Error when embed payload is not a string literal or record literal. *)

 val normalize_tag_for_symbol : string -> string
 (** Convert an embed tag (validated as an attribute id) into a safe fragment
    for inclusion in a single identifier, by replacing '.' with '_'. *)
diff --git a/compiler/frontend/ast_exp_extension.ml b/compiler/frontend/ast_exp_extension.ml
        pexp_desc = Ast_util.record_as_js_object e.pexp_loc self label_exprs;
      }
    | _ -> Location.raise_errorf ~loc "Expect a record expression here")
  | _ -> e
  | _ ->
    (* For configured embed tags, map the payload so that string
       normalization runs within the literal. For all other extensions,
       leave payload untouched to avoid surprising side-effects. *)
    let is_embed_tag =
      !Js_config.collect_embeds && List.mem txt !Js_config.embed_tags
    in
    if is_embed_tag then
      let payload' = self.payload self payload in
      {e with pexp_desc = Parsetree.Pexp_extension ({txt; loc}, payload')}
    else e
 (* For an unknown extension, we don't really need to process further*)
 (* Exp.extension ~loc ~attrs:e.pexp_attributes (
    self.extension self extension) *)
diff --git a/compiler/frontend/bs_ast_invariant.ml b/compiler/frontend/bs_ast_invariant.ml
             Example: type rec t = ..."
        | _ -> super.structure_item self str_item);
    expr =
      (fun self ({pexp_loc = loc} as a) ->
      (fun self ({pexp_loc = loc; pexp_attributes = attrs} as a) ->
        match a.pexp_desc with
        | Pexp_constant (Pconst_string (_s, Some delim))
          when Ast_utf8_string_interp.is_unescaped delim ->
          (* Skip the "uninterpreted delimiters" warning for template/backtick
             strings that are still inside extension payloads or carry the
             template attributes. These will either be rewritten later or have
             already been marked as template literals. *)
          let has_template_attr =
            Ext_list.exists attrs (fun ({txt}, _) ->
                match txt with
                | "res.template" | "res.taggedTemplate" -> true
                | _ -> false)
          in
          if not has_template_attr then
            Bs_warnings.error_unescaped_delimiter loc delim
        | Pexp_constant const -> check_constant loc const
        | Pexp_variant (s, None) when Ext_string.is_valid_hash_number s -> (
          try ignore (Ext_string.hash_number_as_i32_exn s : int32)
Original file line number	Diff line number	Diff line change
Expand Up		@@ -19,6 +19,12 @@ rewatch:
		cargo build --manifest-path rewatch/Cargo.toml --release
		./scripts/copyExes.js --rewatch

		# Generate EmbedLang JSON/OpenAPI schemas into docs/schemas
		schemas: rewatch
		@mkdir -p docs/schemas
		@rewatch/target/release/rescript schema embeds --output-dir docs/schemas --openapi >/dev/null
		@echo "Schemas written to docs/schemas"

		ninja/ninja:
		./scripts/buildNinjaBinary.js

Expand DownExpand Up		@@ -99,4 +105,4 @@ dev-container:

		.DEFAULT_GOAL := build

		.PHONY: build watch rewatch ninja bench dce test test-syntax test-syntax-roundtrip test-gentype test-analysis test-tools test-all lib playground playground-cmijs playground-release artifacts format checkformat clean-gentype clean-rewatch clean clean-all dev-container
		.PHONY: build watch rewatch ninja bench dce test test-syntax test-syntax-roundtrip test-gentype test-analysis test-tools test-all lib playground playground-cmijs playground-release artifacts format checkformat clean-gentype clean-rewatch clean clean-all dev-container schemas
Original file line number	Diff line number	Diff line change
Expand Up		@@ -346,6 +346,15 @@ let command_line_flags : (string * Bsc_args.spec * string) array =
		("-dparsetree", set Clflags.dump_parsetree, "internal debug parsetree");
		("-drawlambda", set Clflags.dump_rawlambda, "internal debug raw lambda");
		("-dsource", set Clflags.dump_source, "internal print source");
		( "-embeds",
		string_call (fun s ->
		Js_config.collect_embeds := true;
		let s = String.trim s in
		Js_config.embed_tags :=
		Ext_string.split_by ~keep_empty:false (fun c -> c = ',') s
		\|> List.map String.trim),
		"internal Collect embed extension occurrences (csv of tags)" );
		(* single-pass embed rewrite via PPX; no separate -rewrite-embeds entry *)
		( "-reprint-source",
		string_call reprint_source_file,
		"internal transform the target ReScript file using PPXes provided, and \
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -71,4 +71,9 @@ let jsx_module_of_string = function
		\| module_name -> Generic {module_name}

		let as_pp = ref false

		(* Embed indexing and rewrite configuration *)
		let collect_embeds = ref false
		let embed_tags : string list ref = ref []

		let self_stack : string Stack.t = Stack.create ()
Original file line number	Diff line number	Diff line change
Expand Up		@@ -100,4 +100,11 @@ val jsx_module_of_string : string -> jsx_module

		val as_pp : bool ref

		(* Embed indexing and rewrite configuration *)
		val collect_embeds : bool ref
		(** When true, emit per-module embed index artifacts during parse *)

		val embed_tags : string list ref
		(** Comma-separated list of tags to collect *)

		val self_stack : string Stack.t
Original file line number	Diff line number	Diff line change
Expand Up		@@ -161,7 +161,13 @@ let implementation ~parser ppf ?outputprefix fname =
		\| Some x -> x
		in
		Res_compmisc.init_path ();
		parser fname
		let ast0 = parser fname in
		(* Emit embed index (if enabled) alongside binary AST output prefix *)
		(try
		Embed_index.write_structure_index ~outprefix:outputprefix ~sourcefile:fname
		ast0
		with _ -> ());
		ast0
		\|> Cmd_ppx_apply.apply_rewriters ~restore:false ~tool_name:Js_config.tool_name
		Ml
		\|> Ppx_entry.rewrite_implementation
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,48 @@
		let get_embed_tag (name : string) : string option =
		let prefix = "embed." in
		let plen = String.length prefix in
		if String.length name > plen && String.sub name 0 plen = prefix then
		Some (String.sub name plen (String.length name - plen))
		else None

		let is_valid_embed_id (s : string) : bool =
		let len = String.length s in
		if len = 0 then false
		else
		let lead = s.[0] in
		let is_letter = function
		\| 'A' .. 'Z' \| 'a' .. 'z' -> true
		\| _ -> false
		in
		let is_ident_char = function
		\| 'A' .. 'Z' \| 'a' .. 'z' \| '0' .. '9' \| '_' -> true
		\| _ -> false
		in
		if not (is_letter lead) then false
		else
		let rec loop i =
		if i >= len then true
		else if is_ident_char s.[i] then loop (i + 1)
		else false
		in
		loop 1

		let invalid_id_error_message =
		"Invalid `id` for embed. Embed `id` must start with a letter, and only \
		contain letters, digits, and underscores."

		let missing_id_error_message = "Embed config record must include `id: string`."

		let invalid_payload_error_message =
		"Embed payload must be either a string literal or a record literal."

		let normalize_tag_for_symbol (tag : string) : string =
		(* Embed tags are already validated by the parser as extension identifiers
		(attr-id with optional dot-separated segments). We only need to make the
		tag segment safe for inclusion in a single identifier by mapping '.' to
		'_'. *)
		let b = Bytes.of_string tag in
		for i = 0 to Bytes.length b - 1 do
		if Bytes.get b i = '.' then Bytes.set b i '_'
		done;
		Bytes.unsafe_to_string b
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,20 @@
		val get_embed_tag : string -> string option
		(** [get_embed_tag name] returns [Some base] when [name] starts with
		the embed prefix "embed." and has a non-empty remainder; otherwise [None]. *)

		val is_valid_embed_id : string -> bool
		(** Validate embed `id`: must start with a letter and contain only
		letters, digits, and underscores. *)

		val invalid_id_error_message : string
		(** Centralized error message for invalid embed `id`. *)

		val missing_id_error_message : string
		(** Error when a config record omits `id` or provides a non-string `id`. *)

		val invalid_payload_error_message : string
		(** Error when embed payload is not a string literal or record literal. *)

		val normalize_tag_for_symbol : string -> string
		(** Convert an embed tag (validated as an attribute id) into a safe fragment
		for inclusion in a single identifier, by replacing '.' with '_'. *)
Original file line number	Diff line number	Diff line change
Expand Up		@@ -84,7 +84,17 @@ let handle_extension e (self : Bs_ast_mapper.mapper)
		pexp_desc = Ast_util.record_as_js_object e.pexp_loc self label_exprs;
		}
		\| _ -> Location.raise_errorf ~loc "Expect a record expression here")
		\| _ -> e
		\| _ ->
		(* For configured embed tags, map the payload so that string
		normalization runs within the literal. For all other extensions,
		leave payload untouched to avoid surprising side-effects. *)
		let is_embed_tag =
		!Js_config.collect_embeds && List.mem txt !Js_config.embed_tags
		in
		if is_embed_tag then
		let payload' = self.payload self payload in
		{e with pexp_desc = Parsetree.Pexp_extension ({txt; loc}, payload')}
		else e
		(* For an unknown extension, we don't really need to process further*)
		(* Exp.extension ~loc ~attrs:e.pexp_attributes (
		self.extension self extension) *)
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -90,8 +90,22 @@ let emit_external_warnings : iterator =
		Example: type rec t = ..."
		\| _ -> super.structure_item self str_item);
		expr =
		(fun self ({pexp_loc = loc} as a) ->
		(fun self ({pexp_loc = loc; pexp_attributes = attrs} as a) ->
		match a.pexp_desc with
		\| Pexp_constant (Pconst_string (_s, Some delim))
		when Ast_utf8_string_interp.is_unescaped delim ->
		(* Skip the "uninterpreted delimiters" warning for template/backtick
		strings that are still inside extension payloads or carry the
		template attributes. These will either be rewritten later or have
		already been marked as template literals. *)
		let has_template_attr =
		Ext_list.exists attrs (fun ({txt}, _) ->
		match txt with
		\| "res.template" \| "res.taggedTemplate" -> true
		\| _ -> false)
		in
		if not has_template_attr then
		Bs_warnings.error_unescaped_delimiter loc delim
		\| Pexp_constant const -> check_constant loc const
		\| Pexp_variant (s, None) when Ext_string.is_valid_hash_number s -> (
		try ignore (Ext_string.hash_number_as_i32_exn s : int32)
Expand Down