[eval] avoid some string allocation for ""

src/macro/eval/evalPrinting.ml

@@ -25,7 +25,6 @@ open EvalField
 open EvalHash
 open EvalString
 
-let rempty = create_ascii ""
 let rbropen = create_ascii "{"
 let rbrclose = create_ascii "}"
 let rbkopen = create_ascii "["
@@ -64,14 +63,14 @@ let rec s_object depth o =
 	create_with_length s (try UTF8.length s with _ -> String.length s)
 
 and s_array depth va =
-	join rempty [
+	join empty_string [
 		rbkopen;
 		EvalArray.join va (s_value depth) rcomma;
 		rbkclose;
 	]
 
 and s_vector depth vv =
-	join rempty [
+	join empty_string [
 		rbkopen;
 		EvalArray.join (EvalArray.create vv) (s_value depth) rcomma;
 		rbkclose;
@@ -90,7 +89,7 @@ and s_enum_value depth ve =
 	match ve.eargs with
 	| [||] -> create_ascii name
 	| vl ->
-		join rempty [
+		join empty_string [
 			create_ascii name;
 			rpopen;
 			join rcomma (Array.to_list (Array.map (s_value (depth + 1)) vl));
@@ -98,8 +97,8 @@ and s_enum_value depth ve =
 		]
 
 and s_proto_kind proto = match proto.pkind with
-	| PClass _ -> join rempty [create_ascii "Class<"; s_hash proto.ppath; rgt]
-	| PEnum _ -> join rempty [create_ascii "Enum<"; s_hash proto.ppath; rgt]
+	| PClass _ -> join empty_string [create_ascii "Class<"; s_hash proto.ppath; rgt]
+	| PEnum _ -> join empty_string [create_ascii "Enum<"; s_hash proto.ppath; rgt]
 	| PInstance | PObject -> assert false
 
 and s_value depth v =

src/macro/eval/evalStdLib.ml

@@ -952,7 +952,7 @@ module StdEReg = struct
 	let split = vifun1 (fun vthis s ->
 		let this = this vthis in
 		let s = decode_string s in
-		if String.length s = 0 then encode_array [encode_string ""]
+		if String.length s = 0 then encode_array [v_empty_string]
 		else begin
 			let max = if this.r_global then -1 else 2 in
 			let l = Pcre.full_split ~iflags:0x2000 ~max ~rex:this.r s in
@@ -1540,9 +1540,9 @@ module StdIntMap = struct
 	let toString = vifun0 (fun vthis ->
 		let this = this vthis in
 		let l = IntHashtbl.fold (fun key vvalue acc ->
-			(join rempty [create_ascii (string_of_int key); create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
+			(join empty_string [create_ascii (string_of_int key); create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
 		let s = join rcomma l in
-		let s = join rempty [rbropen;s;rbrclose] in
+		let s = join empty_string [rbropen;s;rbrclose] in
 		vstring s
 	)
 
@@ -1599,9 +1599,9 @@ module StdStringMap = struct
 	let toString = vifun0 (fun vthis ->
 		let this = this vthis in
 		let l = StringHashtbl.fold (fun _ (key,vvalue) acc ->
-			(join rempty [key; create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
+			(join empty_string [key; create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
 		let s = join rcomma l in
-		let s = join rempty [rbropen;s;rbrclose] in
+		let s = join empty_string [rbropen;s;rbrclose] in
 		vstring s
 	)
 
@@ -1657,9 +1657,9 @@ module StdObjectMap = struct
 	let toString = vifun0 (fun vthis ->
 		let this = this vthis in
 		let l = ValueHashtbl.fold (fun key vvalue acc ->
-			(join rempty [s_value 0 key; create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
+			(join empty_string [s_value 0 key; create_ascii " => "; s_value 0 vvalue]) :: acc) this [] in
 		let s = join rcomma l in
-		let s = join rempty [rbropen;s;rbrclose] in
+		let s = join empty_string [rbropen;s;rbrclose] in
 		vstring s
 	)
 
@@ -2190,7 +2190,7 @@ module StdString = struct
 	let charAt = vifun1 (fun vthis index ->
 		let this = this vthis in
 		let i = decode_int index in
-		if i < 0 || i >= this.slength then encode_string ""
+		if i < 0 || i >= this.slength then v_empty_string
 		else vstring (from_char_code (char_at this i))
 	)
 
@@ -2288,7 +2288,7 @@ module StdString = struct
 		let cl_this = this.slength in
 		let c_pos = decode_int pos in
 		if c_pos >= cl_this then
-			encode_string ""
+			v_empty_string
 		else begin
 			let c_pos = if c_pos < 0 then begin
 				let c_pos = this.slength + c_pos in
@@ -2320,7 +2320,7 @@ module StdString = struct
 		let c_first,c_last = if c_first > c_last then c_last,c_first else c_first,c_last in
 		let c_last = if c_last > cl_this then cl_this else c_last in
 		if c_first > cl_this || c_first = c_last then
-			encode_string ""
+			v_empty_string
 		else begin
 			begin
 				let b_offset1 = get_offset this c_first in
@@ -3236,7 +3236,7 @@ let init_empty_constructors builtins =
 	Hashtbl.add h key_eval_Vector (fun () -> encode_vector_instance (Array.make 0 vnull));
 	Hashtbl.add h key_Date (fun () -> encode_instance key_Date ~kind:(IDate 0.));
 	Hashtbl.add h key_EReg (fun () -> encode_instance key_EReg ~kind:(IRegex {r = Pcre.regexp ""; r_rex_string = create_ascii "~//"; r_global = false; r_string = ""; r_groups = [||]}));
-	Hashtbl.add h key_String (fun () -> encode_string "");
+	Hashtbl.add h key_String (fun () -> v_empty_string);
 	Hashtbl.add h key_haxe_ds_StringMap (fun () -> encode_instance key_haxe_ds_StringMap ~kind:(IStringMap (StringHashtbl.create ())));
 	Hashtbl.add h key_haxe_ds_IntMap (fun () -> encode_instance key_haxe_ds_IntMap ~kind:(IIntMap (IntHashtbl.create ())));
 	Hashtbl.add h key_haxe_ds_ObjectMap (fun () -> encode_instance key_haxe_ds_ObjectMap ~kind:(IObjectMap (Obj.magic (ValueHashtbl.create 0))));

src/macro/eval/evalString.ml

@@ -34,6 +34,10 @@ let create_with_length s length = {
 	soffsets = [];
 }
 
+let empty_string = create_ascii ""
+
+let v_empty_string = VString empty_string
+
 let create_unknown s =
 	vstring (create_with_length s (try UTF8.length s with _ -> String.length s))