Re: Token value in custom error reporting

[Hans Åberg]

> On 18 Jun 2020, at 18:56, Akim Demaille <akim@lrde.epita.fr> wrote:
> 
>> Le 18 juin 2020 à 14:54, Hans Åberg <haberg-1@telia.com> a écrit :
>> 
>> In my C++ parser, the lexer has rule
>> .          { return my_parser::token::token_error; }
>> 
>> When it is triggers, I get the error:
>> <file>:21.1: error: syntax error, unexpected token error
>> 
>> It might be nicer to actually write out this token, though.
> 
> I have already explained what I don't think this is a good idea.
> 
> https://lists.gnu.org/r/help-bison/2020-06/msg00017.html
> 
> I also have explained that scanner errors should be handled
> by the scanner.  For instance, in the bistro, you can read:
> 
> int
> yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
> {
>  int c;
> 
> [...]
> 
>  switch (c)
>    {
> [...]
>      // Stray characters.
>    default:
>      yyerror (yylloc, "syntax error: invalid character: %c", c);
>      return TOK_YYerror;
>    }
> }
> 
> Cheers!

Is that not the case, which I responded to, where you get double error 
messages, both from the lexer and parser?