Re: Porting Lua to Windows Mobile Professional 6.5.3

[Marc Balmer <marc@...>]

Am 02.06.2011 18:24, schrieb Marc Balmer:
> Am 02.06.2011 18:19, schrieb Marc Balmer:
> > Am 02.06.2011 18:05, schrieb Luiz Henrique de Figueiredo:
> > > > syntax error: [string "return 42"]:1: malformed number near '42ÿ'
> > >
> > > Ah, ÿ is 0xFF. So, somehow -1 is getting mapped into 0xFF.
> > > It seems to be a faulty isdigit, which is mapping -1 to 0xFF *and*
> > > thinking 0xFF is a digit! Try using your own isdigit...
> >
> > Where does that -1 come from? I replaced isdigit() in read_numeral by
> > the following, no change:
> >
> > static int
> > isadigit(char c)
> > {
> > if (c >= '0' && c <= '9')
> > return 1;
> > return 0;
> > }
> >
> >
> >
> > > If you want to trace this, the place to start is read_numeral in llex.c.
>
> isalnum(-1) indeed returns != 0 on Windows Mobile. Looks like a
> signed/unsigned char, Unicode or related problem to me.

When I change read_numeral from

static void read_numeral (LexState *ls, SemInfo *seminfo) {
  lua_assert(isdigit(ls->current));
  do {
    save_and_next(ls);
  } while (isdigit(ls->current) || ls->current == '.');
  if (check_next(ls, "Ee"))  /* `E'? */
    check_next(ls, "+-");  /* optional exponent sign */
  while (isalnum(ls->current) || ls->current == '_')
    save_and_next(ls);
  save(ls, '\0');
  buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal 
point */
  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r))  /* format error? */
    trydecpoint(ls, seminfo); /* try to update decimal point separator */
}

to

static void read_numeral (LexState *ls, SemInfo *seminfo) {
  lua_assert(isdigit(ls->current));
  do {
    save_and_next(ls);
  } while (isdigit(ls->current) || ls->current == '.');
  if (check_next(ls, "Ee"))  /* `E'? */
    check_next(ls, "+-");  /* optional exponent sign */
  while (isdigit(ls->current) || ls->current == '_')
    save_and_next(ls);
  save(ls, '\0');
  buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal 
point */
  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r))  /* format error? */
    trydecpoint(ls, seminfo); /* try to update decimal point separator */
}


It works.  Note that I changed the "isalnum" to "isdigit" in the second 
loop.  Why is isalnum() being used there?