From: Alex Young <alex@...>
Date: 2012-11-02T00:34:12+09:00
Subject: [ruby-core:48711] Re: [ruby-trunk - Feature #6973] Add an #integral? method to Numeric to test for whole-number values

On 31/10/12 13:03, alexeymuranov (Alexey Muranov) wrote:
>
> Issue #6973 has been updated by alexeymuranov (Alexey Muranov).
>
>
> regularfry (Alex Young) wrote:
>
>>
>>   So if I knowingly and correctly construct a calculation which cannot
>>   contain such an error, Ruby should tell me that it's wrong?
>>
>
> Alex, can you give an example, please?

Trivially?  x * 2.0 for x small enough not to overflow.

There's a more interesting vein of examples where this sort of thing 
crops up if you google for "error-free transformations", like the 2Sum 
and Fast2Sum algorithms.

-- 
Alex


>
> ----------------------------------------
> Feature #6973: Add an #integral? method to Numeric to test for whole-number values
> https://bugs.ruby-lang.org/issues/6973#change-32110
>
> Author: regularfry (Alex Young)
> Status: Assigned
> Priority: Normal
> Assignee: mrkn (Kenta Murata)
> Category: core
> Target version: next minor
>
>
> Numeric#integer? checks whether an instance is an Integer.  It is often useful to check whether the value of a non-Integer variable is actually a whole number, and the #integer? method doesn't help here.
>
> This patch adds Numeric#integral?, which performs this check.
>
>