Re: Strange behaviour in hexadecimal numbers

[KHMan <keinhong@...>]

On 1/20/2012 1:05 AM, Alexandra Barros wrote:
> Hi all,
>
> I stumbled upon a weird behaviour in hexadecimal constants in Lua
> 5.2.0 (and LuaJIT 2.0.0-beta8).
>
> When adding a hexadecimal number ending with E it gives a "malformed
> number" error, unless I insert a blank space between E and the plus
> sign. Looks like the lexer is tokenizing it as an invalid floating
> point number. Tests follow...
>
> > print(0xE)
> 14
> > print(0xE+9)
> stdin:1: malformed number near '0xE+9'
> > print(0xE +9)
> 23
> > print(0xA+9)
> 19

Sorry, I was hasty. :-P I agree that it is not a hex float.

This is a limitation of the lexer. It grabs a lot but test the 
kaboodle as one unit. Triggered by 'E', from llex.c:

  do {
    save_and_next(ls);
    if (check_next(ls, "EePp"))  /* exponent part? */
      check_next(ls, "+-");  /* optional exponent sign */
  } while (lislalnum(ls->current) || ls->current == '.');


Would be nice to have it fixed...

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia