Handle windows CRLF correct. (#425)

* Handle windows CRLF correct.

`\r\n` should be picked up as one line break, not two.

* Add comment about CRLF

Co-authored-by: Iwan <[email protected]>

Author: IwanKaramazow

.depend

@@ -72,4 +72,4 @@ src/res_scanner.cmi : src/res_token.cmx src/res_diagnostics.cmi
 src/res_token.cmx : src/res_comment.cmx
 tests/res_test.cmx : src/res_token.cmx src/res_parser.cmx \
     src/res_outcome_printer.cmx src/res_multi_printer.cmx src/res_io.cmx \
-    src/res_driver.cmx
+    src/res_driver.cmx src/res_core.cmx

src/res_scanner.ml

@@ -98,9 +98,12 @@ let _printDebug ~startPos ~endPos scanner token =
 let next scanner =
   let nextOffset = scanner.offset + 1 in
   (match scanner.ch with
-  | '\n' | '\r' ->
+  | '\n' ->
     scanner.lineOffset <- nextOffset;
     scanner.lnum <- scanner.lnum + 1;
+    (* What about CRLF (\r + \n) on windows?
+     * \r\n will always be terminated by a \n
+     * -> we can just bump the line count on \n *)
   | _ -> ());
   if nextOffset < String.length scanner.src then (
     scanner.offset <- nextOffset;

tests/res_test.ml

@@ -147,8 +147,32 @@ module ParserApiTest = struct
     assert (parser.token = Res_token.Let);
     print_endline "✅ Parser make: initializes parser and checking offsets"
 
+  let unixLf () =
+    let src = "let x = 1\nlet y = 2\nlet z = 3" in
+    let parser = Res_parser.make src "test.res" in
+    (match Res_core.parseImplementation parser with
+    | [x; y; z] ->
+      assert (x.pstr_loc.loc_start.pos_lnum = 1);
+      assert (y.pstr_loc.loc_start.pos_lnum = 2);
+      assert (z.pstr_loc.loc_start.pos_lnum = 3)
+    | _ -> assert false);
+    print_endline "✅ Parser handles LF correct"
+
+  let windowsCrlf () =
+    let src = "let x = 1\r\nlet y = 2\r\nlet z = 3" in
+    let parser = Res_parser.make src "test.res" in
+    (match Res_core.parseImplementation parser with
+    | [x; y; z] ->
+      assert (x.pstr_loc.loc_start.pos_lnum = 1);
+      assert (y.pstr_loc.loc_start.pos_lnum = 2);
+      assert (z.pstr_loc.loc_start.pos_lnum = 3)
+    | _ -> assert false);
+    print_endline "✅ Parser handles CRLF correct"
+
   let run () =
     makeDefault();
+    unixLf();
+    windowsCrlf()
 
 end