Issue #5321 has been updated by tadayoshi funaba.


i've proposed this before 1.9.
and i've virtually used those predicates in Complex/Rational internally.

i've taken those from scheme.
scheme's one accept also complex number.
i think those should be instance methods.

> (exact? 1+0i)
#t
> (exact? 1+0.0i)
#f

bye

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Feature #5321: Introducing Numeric#exact? and Numeric#inexact?
http://redmine.ruby-lang.org/issues/5321

Author: Kenta Murata
Status: Assigned
Priority: Normal
Assignee: Yukihiro Matsumoto
Category: 
Target version: 


Ruby has several numeric classes such as Integer.
These classes are classified whether their instances represent numbers exactly.
According to this, Integer and Rational are exact, and Float and BigDecimal are inexact because they're always including error.
The exactness of a Complex depends on its real and imaginary parts.

Now, Ruby's numeric classes doesn't provide predicators to investigate the exactness of their instances.
So, if we want to examine whether a number is exactly zero, we must investigate the class of the number.
I want simple way to examine the number exactness.

I propose to introduce Numeric#exact? and/or Numeric#inexact? for resolving this inconvenience.



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