support utf8 in tagged templates (fixes #6750)

Author: tsnobip

CHANGELOG.md

@@ -27,6 +27,7 @@
 
 #### :bug: Bug Fix
 
+- Fix encoding inside tagged template literals. https://github.com/rescript-lang/rescript-compiler/pull/6810
 - Fix unhandled cases for exotic idents (allow to use exotic PascalCased identifiers for types). https://github.com/rescript-lang/rescript-compiler/pull/6777
 - PPX v4: mark props type in externals as `@live` to avoid dead code warnings for prop fields in the editor tooling. https://github.com/rescript-lang/rescript-compiler/pull/6796
 - Fix unused attribute check for `@as`. https://github.com/rescript-lang/rescript-compiler/pull/6795

jscomp/syntax/src/res_core.ml

@@ -2284,8 +2284,7 @@ and parse_template_expr ?prefix p =
     match prefix with
     | Some {txt = Longident.Lident (("js" | "j" | "json") as prefix); _} ->
       Some prefix
-    | Some _ -> None
-    | None -> Some "js"
+    | _ -> Some "js"
   in
   let start_pos = p.Parser.start_pos in
 

jscomp/syntax/tests/parsing/other/expected/stringLiterals.res.txt

@@ -0,0 +1,20 @@
+let s = {js|some unicode é £ |js}
+let s = (({js|foo|js})[@res.template ])
+let s =
+  (((((({js|foo |js})[@res.template ]) ^ bar)[@res.template ]) ^
+      (({js| baz|js})[@res.template ]))
+  [@res.template ])
+let s =
+  (((((({js|some unicode é |js})[@res.template ]) ^ bar)[@res.template ]) ^
+      (({js| £ |js})[@res.template ]))
+  [@res.template ])
+let s = ((x [|(({js|foo|js})[@res.template ])|] [||])[@res.taggedTemplate ])
+let s =
+  ((x [|(({js|foo |js})[@res.template ]);(({js| baz|js})[@res.template ])|]
+      [|bar|])
+  [@res.taggedTemplate ])
+let s =
+  ((x
+      [|(({js|some unicode é |js})[@res.template ]);(({js| £ |js})
+        [@res.template ])|] [|bar|])
+  [@res.taggedTemplate ])

jscomp/syntax/tests/parsing/other/stringLiterals.res

@@ -0,0 +1,7 @@
+let s = "some unicode é £ "
+let s = `foo`
+let s = `foo ${bar} baz`
+let s = `some unicode é ${bar} £ `
+let s = x`foo`
+let s = x`foo ${bar} baz`
+let s = x`some unicode é ${bar} £ `

jscomp/test/tagged_template_test.js

@@ -26,7 +26,7 @@ let foo = (strings, values) => {
   res.contents ++ strings[valueCount]
 }
 
-let res = foo`| 5 * 10 = ${5} |`
+let res = foo`| 5 × 10 = ${5} |`
 
 Mt.from_pair_suites(
   "tagged templates",
@@ -44,8 +44,8 @@ Mt.from_pair_suites(
       () => Eq(length, 52),
     ),
     (
-      "with rescript function, it should return a string with the correct interpolations",
-      () => Eq(res, "| 5 * 10 = 50 |"),
+      "with rescript function, it should return a string with the correct encoding and interpolations",
+      () => Eq(res, "| 5 × 10 = 50 |"),
     ),
     (
       "a template literal tagged with json should generate a regular string interpolation for now",