exact_zero

ExactZero

This gem provides Numeric#exact_zero?, which determine the occurrence of zero division error in advance.

There are some ideas of the judgement in the article https://qiita.com/HMMNRST/items/6cf7e7cc853e5d627a72. (Japanese)

Installation

Add this line to your application's Gemfile:

gem 'exact_zero'

And then execute:

$ bundle

Or install it yourself as:

$ gem install exact_zero

Usage

require 'exact_zero'

Integer("0")   .exact_zero?   #=> true
Rational("0")  .exact_zero?   #=> true
Float("0")     .exact_zero?   #=> false
Complex("0")   .exact_zero?   #=> true
Complex("0.0i").exact_zero?   #=> false

require 'bigdecimal'
BigDecimal("0").exact_zero?   #=> false

Example 1: avoid ZeroDivisionError

require 'exact_zero'

class Numeric
	def reciprocal
		1.quo(self)
	end

	def reciprocal_safe
		exact_zero? ? nil : reciprocal
	end
end

num1 = 0.0
num1.reciprocal        #=> Infinity
num1.reciprocal_safe   #=> Infinity

num2 = Complex(0, 0/1r)
num2.reciprocal        #=> ZeroDivisionError: divided by 0
num2.reciprocal_safe   #=> nil

Example 2: Complex to Real

require 'exact_zero'

class Complex
	%w(to_f to_r to_i).each do |name|
		define_method("try_#{name}") do
			imag.exact_zero? ? send(name) : nil
		end
	end
end

num1 = Complex("3+0/1i")
num1.to_f       #=> 3.0
num1.try_to_f   #=> 3.0

num2 = Complex("3+0.0i")
num2.to_f       #=> RangeError: can't convert 3+0.0i into Float
num2.try_to_f   #=> nil

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/hmmnrst/exact_zero.

License

The gem is available as open source under the terms of the MIT License.