From: Kenta Murata <muraken@...>
Date: 2011-09-14T09:18:38+09:00
Subject: [ruby-core:39533] Re: [Ruby 1.9 - Feature #5310][Open] Integral objects

Hi, 

On Wednesday, September 14, 2011 at 06:23 , brian ford wrote:
> There is some inconsistency between your proposal and what has been implemented:

We can change the implementation according to the proposal if accepted.

> A Float value is a machine approximation of a mathematical real
> number. A BigDecimal is an exact representation of a real number. The
> mathematical real numbers embed the integers.

You are not right.
A BigDecimal is a floating-point number same as a Float except for internal representation.
So, A BigDecimal is also approximation of a real number,
in other words, a BigDecimal has error as well as a Float does.
It is right understanding because I am the master of bigdecimal.

> It is untrue that Float numbers cannot be consistently represented as
> integral values. It is merely up to the language to define them as
> such. Ruby already takes liberties with defining mathematical
> operations (see http://redmine.ruby-lang.org/issues/3289).

I know. I suggest to change for number system.

> To remove #to_int from Float and BigDecimal and partially from
> Rational and Complex introduces typing concepts where none are needed,
> breaks consistent polymorphism, and breaks compatibility with 1.8 and
> prior 1.9.

Yes, my proposal introduces incompatibility, so I propose this for 2.0.

-- 
Kenta Murata
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