Function read_numeral

extlibs/lua/src/llex.c:225–254

LUA_NUMBER */ ** This function is quite liberal in what it accepts, as 'luaO_str2num' ** will reject ill-formed numerals. Roughly, it accepts the following ** pattern: ** ** %d(%x|%.|([Ee][+-]?))* | 0[Xx](%x|%.|([Pp][+-]?))* ** ** The only tricky part is to accept [+-] only after a valid exponent ** mark, to avoid reading '3-4' or '0xe+1' as a single number. ** ** The caller might have already r

** The caller might have already read an initial dot.
*/
static int read_numeral (LexState *ls, SemInfo *seminfo) {
  TValue obj;
  const char *expo = "Ee";
  int first = ls->current;
  lua_assert(lisdigit(ls->current));
  save_and_next(ls);
  if (first == '0' && check_next2(ls, "xX"))  /* hexadecimal? */
    expo = "Pp";
  for (;;) {
    if (check_next2(ls, expo))  /* exponent mark? */
      check_next2(ls, "-+");  /* optional exponent sign */
    else if (lisxdigit(ls->current) || ls->current == '.')  /* '%x|%.' */
      save_and_next(ls);
    else break;
  }
  if (lislalpha(ls->current))  /* is numeral touching a letter? */
    save_and_next(ls);  /* force an error */
  save(ls, '\0');
  if (luaO_str2num(luaZ_buffer(ls->buff), &obj) == 0)  /* format error? */
    lexerror(ls, "malformed number", TK_FLT);
  if (ttisinteger(&obj)) {
    seminfo->i = ivalue(&obj);
    return TK_INT;
  }
  else {
    lua_assert(ttisfloat(&obj));
    seminfo->r = fltvalue(&obj);
    return TK_FLT;
  }
}


/*