Change the behaviour introduced by commit:bcf40231

[ 'abc'ab ] is now parsed as [ 'abc' ab ] to maintain backward compatibility.
Change the warning message accordingly.

parser/ulexer.ml

@@ -294,8 +294,10 @@ let rec token = lexer
  | ["?+*"] "?" | "#" ->
      return lexbuf (KEYWORD (L.utf8_lexeme lexbuf))
 
- (* the three followning rules work together and are replicated in the
-    comment lexer *)
+ (*
+   BEGIN lexing of single quoted string/polymorphic variables
+         these rules should also be mimicked in the comment lexer.
+ *)
 
  | "'" ([^ '\t' '\n' '\r' '\''] | '\\' '\'')* "'" (not_ncname_letter | eof) ->
    (* two single quotes not followed by an xml_letter must be a string
@@ -305,11 +307,12 @@ let rec token = lexer
    do_string lexbuf
 
  | "'" ncname "'" ncname ->
+   (* Tokenize [ 'abc'abc ] as [ 'abc' abc ], to ensure backward compatibility with 0.x CDuce *)
    let s = L.utf8_lexeme lexbuf in
    warning lexbuf
-     (Printf.sprintf "ambiguous sequence of polymorphic variables (%s). Add a space before the second quote." s);
+     (Printf.sprintf "string literal followed by an identifier (%s) is ambiguous. Add a space after the second quote." s);
    L.rollback lexbuf;
-   do_variable lexbuf
+   do_string lexbuf
 
  | "'" ncname ->
    (* then try to read it as variable *)
@@ -321,6 +324,9 @@ let rec token = lexer
       character as a string to get a decent error message *)
      L.rollback lexbuf;
    do_string lexbuf
+(*
+  END lexing of single quoted string/polymorphic variables
+*)
 
  | "(*" ->
      in_comment := true;
@@ -359,13 +365,13 @@ and comment start = lexer
   | "*)" ->
       ()
 
-
-  | "'" ([^ '\t' '\n' '\r' '\''] | '\\' '\'')* "'" (not_ncname_letter | eof) ->
+  | ("'" ([^ '\t' '\n' '\r' '\''] | '\\' '\'')* "'" (not_ncname_letter | eof))
+  | ("'" ncname "'" ncname) ->
+     (* merge these two cases, and don't emit a warning since we are in a comment *)
     L.rollback lexbuf;
     ignore (do_string lexbuf);
     comment start lexbuf
 
-
  | "'" ncname -> comment start lexbuf