From: Brian Palmer <rubytalk@...>
Date: 2006-07-10T09:12:32+09:00
Subject: Re: Marshal's handling of floats

On Jul 9, 2006, at 5:52 PM, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: Marshal's handling of floats"
>     on Sun, 9 Jul 2006 13:31:59 +0900, Brian Palmer  
> <rubytalk@brian.codekitchen.net> writes:
>
> |I was thinking about writing a patch to modify how Marshal handles
> |floats, right now it dumps them using sprintf(3) and stores the
> |resulting string in the Marshal stream. I'd like to see it handle
> |floats the same way that Array#pack does:
> |
> |[400.53].pack('g').length == 4
> |[400.53].pack('G').length == 8
> |
> |while
> |
> |Marshal.dump(400.53).length - 3 == 22
> |(and is slower, to boot)
> |
> |I want to make sure, though, that this would be an acceptable patch.
>
> There are issues:
>
>   * pack('g') would not work on non-IEEE floating machines.
>   * changing marshal format in incompatible way causes a lot of
>     troubles, so that it should be avoided if possible.
>
> I think we can merge it for 1.9 (if we address IEEE754 issue).
>
> 							matz.
>

Yes, that's a biggie. I didn't realize that ruby compiled on non-IEEE  
machines, but it makes sense now that I think about it. I think this  
is out of my league, I suppose it would require integrating a  
floating-point emulation library into ruby on such platforms, and  
having that library handle the packing/marshaling, or even using that  
library to back all Float objects on such platforms. I think that for  
my purposes it makes more sense to just write a separate Marshal-type  
extension library, since I only plan to target IA32, IA64 and Apple  
G4/G5.

Thanks for the response!

-- Brian