From: Mark Hubbart <discord@...>
Date: 2004-05-06T07:31:29+09:00
Subject: Re: Bug in Float literal (1e-19 == 0) Re: 0.0 sign


On May 5, 2004, at 3:13 PM, Tobias Peters wrote:

> What I find much more problematic than 0.0 having a sign is that ruby 
> treats
>
> 0.0000000000000000001 == 0.0 as true.
>
> If I've counted correct that should be 1 * 10^-19. Doubles can 
> represent Numbers down to approx. 10^-300.
>
> 1e-300 == 0.0 is false in ruby, as it should be.
>
> There must be a bug in the interpreter, where it reads Float literals.

For me, it cuts off after 1e-17:

   0.000_000_000_000_000_01
     ==>1e-17
   0.000_000_000_000_000_001
     ==>0.0
I'm not sure it's a bug in float parsing, since you can go:
   1e-18
     ==>1e-18
   1e-300
     ==>1e-300
...which would be preferable to typing in all those zeros anyway. But I 
would be curious to know why they decided to truncate long float 
literals?

--Mark