From: Robert Klemme <shortcutter@...>
Date: 2009-04-14T16:43:05+09:00
Subject: Re: a few thoughts for ruby...

Please do not top post.

2009/4/14 Julian Leviston <julian@coretech.net.au>:
> Why aren't they? What do you mean by this out of interest?

09:41:50 ~$ ruby19 x.rb
Float              0.00000000010000000827
BigDecimal         0.00000000010000000000
Float              0.00000000000000000827
BigDecimal         0.00000000000000000000
false
true
09:41:52 ~$ cat x.rb

require 'bigdecimal'

f = (1.0 + 1.0e-10) - 1.0
bd = (BigDecimal.new("1.0") + BigDecimal.new("1.0e-10")) - BigDecimal.new("1.0")

printf "%-10s %30.20f\n", f.class, f
printf "%-10s %30.20f\n", bd.class, bd

f -= 1.0e-10
bd -= BigDecimal.new "1.0e-10"

printf "%-10s %30.20f\n", f.class, f
printf "%-10s %30.20f\n", bd.class, bd

puts f == 0.0, bd == 0.0
09:41:57 ~$

> On 11/04/2009, at 6:45 PM, Robert Klemme <shortcutter@googlemail.com> wrote:
>
>> Seems reasonable at first sight but the absence might have a reason. For
>> example, by making the conversion to String explicit it is more obvious that
>> float and BigDecimal are not really compatible.

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end