Ruby | 範囲を扱うクラスを自作する #ruby

概要

範囲を扱うクラスを自作します。

Ruby で範囲（ Range ）を扱うためには、
<=> と succ の二つのメソッドを実装する必要があります。

仕様

年齢を扱うクラスを範囲で扱えるようにします。

サンプルコード

require 'tbpgr_utils'

class Age
  attr_accessor :age

  def initialize(age)
    @age = age
  end

  def adult?
    !!(age >= 20)
  end

  def minor?
    !adult?
  end

  def succ
    copy = self.dup
    copy.age += 1
    copy
  end

  def <=>(other)
    age <=> other.age
  end
end

bulk_puts_eval binding, <<-EOS
(Age.new(18)..Age.new(22)).to_a
Range.new(Age.new(18), Age.new(22)).to_a
(Age.new(18)...Age.new(22)).to_a
Range.new(Age.new(18), Age.new(22), true).to_a
(Age.new(18)..Age.new(22)).min
(Age.new(18)..Age.new(22)).max
EOS

(Age.new(18)..Age.new(22)).each do |a|
  bulk_puts_eval binding, <<-EOS
a.age
a.adult?
a.minor?
  EOS
end

__END__
下記はTbpgrUtils gemの機能
bulk_puts_eval

https://rubygems.org/gems/tbpgr_utils
https://github.com/tbpgr/tbpgr_utils

出力

(Age.new(18)..Age.new(22)).to_a
# => [#<Age:0x00000600cb5b28 @age=18>, #<Age:0x00000600cb5a60 @age=19>, #<Age:0x00000600cb5a38 @age=20>, #<Age:0x00000600cb5a10 @age=21>, #<Age:0x00000600cb59e8 @age=22>]
Range.new(Age.new(18), Age.new(22)).to_a
# => [#<Age:0x00000600cb5358 @age=18>, #<Age:0x00000600cb5290 @age=19>, #<Age:0x00000600cb5268 @age=20>, #<Age:0x00000600cb5240 @age=21>, #<Age:0x00000600cb5218 @age=22>]
(Age.new(18)...Age.new(22)).to_a
# => [#<Age:0x00000600cb4c28 @age=18>, #<Age:0x00000600cb4b60 @age=19>, #<Age:0x00000600cb4b38 @age=20>, #<Age:0x00000600cb4b10 @age=21>]
Range.new(Age.new(18), Age.new(22), true).to_a 
# => [#<Age:0x00000600cb44a8 @age=18>, #<Age:0x00000600cb43e0 @age=19>, #<Age:0x00000600cb43b8 @age=20>, #<Age:0x00000600cb4390 @age=21>]
(Age.new(18)..Age.new(22)).min                 # =>  #<Age:0x00000600bf2448 @age=18>
(Age.new(18)..Age.new(22)).max                 # =>  #<Age:0x00000600bf1fe8 @age=22>
a.age    # => 18
a.adult? # => false
a.minor? # => true
a.age    # => 19
a.adult? # => false
a.minor? # => true
a.age    # => 20
a.adult? # => true
a.minor? # => false
a.age    # => 21
a.adult? # => true
a.minor? # => false
a.age    # => 22
a.adult? # => true
a.minor? # => false