From: Diogo Almeida <diogo.borges.almeida@...>
Date: 2010-07-13T21:09:04+09:00
Subject: Ruby 1.9.2 float precision

Hello,

The Liquid templating engine has the following tests passing till ruby
1.9.2 rc1:

assert_template_result "4.66666666666667", "{{ 14 | divided_by:'3.0' }}"
#equals to 14/3.0 in irb
assert_template_result "6.3", "{{ '2.1' | times:3 }}" #equals to 2.1*3
in irb

However, as far as I could understand, the float precision has been
changed with RC1 and the first assertion now returns 15 decimal digits
instead of 14:
ruby-1.9.2-rc1 > 14/3.0
 => 4.666666666666667

And the second returns the same 15 decimal digits instead of 1:
ruby-1.9.2-rc1 > 2.1*3
 => 6.300000000000001

Even though I realize that the templating engine should not be messing
with the ruby pre-defined precisions, I would like to ask what would be
the recommended way to get all ruby versions to behave the same?

For instance, I've noticed that in both 1.9.1 and 1.9.2-rc1 the
instruction (14/3.0).to_r returns the exact same rational, just
differing when using the #to_f

Best regards
-- 
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