Add exercise files

ruby-book/Rakefile

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+require 'rake/testtask'
+
+Rake::TestTask.new do |t|
+  t.pattern = 'test/**/*_test.rb'
+end
+
+task default: :test

ruby-book/lib/bank.rb

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+require './lib/deep_freezable'
+
+class Bank
+  extend DeepFreezable
+
+  CURRENCIES = deep_freeze({ 'Japan' => 'yen', 'US' => 'dollar', 'India' => 'rupee' })
+end

ruby-book/lib/convert_hash_syntax.rb

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+def convert_hash_syntax(old_syntax)
+  old_syntax.gsub(/:(\w+) *=> */, '\1: ')
+end

ruby-book/lib/convert_length.rb

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+UNITS = { m: 1.0, ft: 3.28, in: 39.37 }
+def convert_length(length, from: :m, to: :m)
+  (length / UNITS[from] * UNITS[to]).round(2)
+end

ruby-book/lib/deep_freezable.rb

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+module DeepFreezable
+  def deep_freeze(array_or_hash)
+    case array_or_hash
+    when Array
+      array_or_hash.each do |element|
+        element.freeze
+      end
+    when Hash
+      array_or_hash.each do |key, value|
+        key.freeze
+        value.freeze
+      end
+    end
+    array_or_hash.freeze
+  end
+end

ruby-book/lib/effects.rb

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+module Effects
+  def self.reverse
+    ->(words) do
+      words.split(' ').map(&:reverse).join(' ')
+    end
+  end
+
+  def self.echo(rate)
+    ->(words) do
+      words.chars.map { |c| c == ' ' ? c : c * rate }.join
+    end
+  end
+
+  def self.loud(level)
+    ->(words) do
+      words.split(' ').map { |word| word.upcase + '!' * level }.join(' ')
+    end
+  end
+end

ruby-book/lib/fizz_buzz.rb

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+def fizz_buzz(n)
+  if n % 15 == 0
+    'Fizz Buzz'
+  elsif n % 3 == 0
+    'Fizz'
+  elsif n % 5 == 0
+    'Buzz'
+  else
+    n.to_s
+  end
+end

ruby-book/lib/fizz_buzz_chapter_02.rb

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+def fizz_buzz(n)
+  if n % 15 == 0
+    'Fizz Buzz'
+  elsif n % 3 == 0
+    'Fizz'
+  elsif n % 5 == 0
+    'Buzz'
+  else
+    n.to_s
+  end
+end
+
+puts fizz_buzz(1)
+puts fizz_buzz(2)
+puts fizz_buzz(3)
+puts fizz_buzz(4)
+puts fizz_buzz(5)
+puts fizz_buzz(6)
+puts fizz_buzz(15)

ruby-book/lib/gate.rb

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+# 改札機を表すクラス
+class Gate
+  STATIONS = [:umeda, :juso, :mikuni] # :nodoc:
+  FARES = [150, 190] # :nodoc:
+
+  # Gateオブジェクトの作成
+  # ==== 引数
+  # * +name+ - 駅名
+  def initialize(name)
+    @name = name
+  end
+
+  # 改札機を通って駅に入場する
+  # ==== 引数
+  # * +ticket+ - 切符
+  def enter(ticket)
+    ticket.stamp(@name)
+  end
+
+  # 改札機を通って駅から出場する
+  # ==== 引数
+  # * +ticket+ - 切符
+  # ==== 戻り値
+  # * +boolean+ - 運賃が足りていれば+true+、不足していれば+false+
+  def exit(ticket)
+    fare = calc_fare(ticket)
+    fare <= ticket.fare
+  end
+
+  private
+
+  def calc_fare(ticket)
+    from = STATIONS.index(ticket.stamped_at)
+    to = STATIONS.index(@name)
+    distance = to - from
+    FARES[distance - 1]
+  end
+end

ruby-book/lib/regexp_checker.rb

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+print 'Text?: '
+text = gets.chomp
+
+begin
+  print 'Pattern?: '
+  pattern = gets.chomp
+  regexp = Regexp.new(pattern)
+rescue RegexpError => e
+  puts "Invalid pattern: #{e.message}"
+  retry
+end
+
+matches = text.scan(regexp)
+if matches.size > 0
+  puts "Matched: #{matches.join(', ')}"
+else
+  puts "Nothing matched."
+end

ruby-book/lib/rgb.rb

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+def to_hex(r, g, b)
+  [r, g, b].inject('#') do |hex, n|
+    hex + n.to_s(16).rjust(2, '0')
+  end
+end
+
+def to_ints(hex)
+  hex.scan(/\w\w/).map(&:hex)
+end

ruby-book/lib/team.rb

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+require './lib/deep_freezable'
+
+class Team
+  extend DeepFreezable
+
+  COUNTRIES = deep_freeze(['Japan', 'US', 'India'])
+end

ruby-book/lib/ticket.rb

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+class Ticket
+  attr_reader :fare, :stamped_at
+
+  def initialize(fare)
+    @fare = fare
+  end
+
+  def stamp(name)
+    @stamped_at = name
+  end
+end

ruby-book/lib/word_synth.rb

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+class WordSynth
+  def initialize
+    @effects = []
+  end
+
+  def add_effect(effect)
+    @effects << effect
+  end
+
+  def play(original_words)
+    @effects.inject(original_words) do |words, effect|
+      effect.call(words)
+    end
+  end
+end

ruby-book/test/convert_hash_syntax_test.rb

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+require 'minitest/autorun'
+require './lib/convert_hash_syntax'
+
+class ConvertHashSyntaxTest < Minitest::Test
+  def test_convert_hash_syntax
+    old_syntax = <<~TEXT
+      {
+        :name => 'Alice',
+        :age=>20,
+        :gender  =>  :female
+      }
+    TEXT
+    expected = <<~TEXT
+      {
+        name: 'Alice',
+        age: 20,
+        gender: :female
+      }
+    TEXT
+    assert_equal expected, convert_hash_syntax(old_syntax)
+  end
+end

ruby-book/test/convert_length_test.rb

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+require 'minitest/autorun'
+require './lib/convert_length'
+
+class ConvertLengthTest < Minitest::Test
+  def test_convert_length
+    assert_equal 39.37, convert_length(1, from: :m, to: :in)
+    assert_equal 0.38, convert_length(15, from: :in, to: :m)
+    assert_equal 10670.73, convert_length(35000, from: :ft, to: :m)
+  end
+end

ruby-book/test/deep_freezable_test.rb

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+require 'minitest/autorun'
+require './lib/bank'
+require './lib/team'
+
+class DeepFreezableTest < Minitest::Test
+  def test_deep_freeze_to_array
+    # 配列の値は正しいか？
+    assert_equal ['Japan', 'US', 'India'], Team::COUNTRIES
+    # 配列自身がfreezeされているか？
+    assert Team::COUNTRIES.frozen?
+    # 配列の要素がすべてfreezeされているか？
+    assert Team::COUNTRIES.all? { |country| country.frozen? }
+  end
+
+  def test_deep_freeze_to_hash
+    # ハッシュの値は正しいか？
+    assert_equal(
+      { 'Japan' => 'yen', 'US' => 'dollar', 'India' => 'rupee' },
+      Bank::CURRENCIES
+    )
+    # ハッシュ自身がfreezeされているか？
+    assert Bank::CURRENCIES.frozen?
+    # ハッシュの要素（キーと値）がすべてfreezeされているか？
+    assert Bank::CURRENCIES.all? { |key, value| key.frozen? && value.frozen? }
+  end
+end

ruby-book/test/effects_test.rb

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+require 'minitest/autorun'
+require './lib/effects'
+
+class EffectsTest < Minitest::Test
+  def test_reverse
+    effect = Effects.reverse
+    assert_equal 'ybuR si !nuf', effect.call('Ruby is fun!')
+  end
+
+  def test_echo
+    effect = Effects.echo(2)
+    assert_equal 'RRuubbyy iiss ffuunn!!', effect.call('Ruby is fun!')
+
+    effect = Effects.echo(3)
+    assert_equal 'RRRuuubbbyyy iiisss fffuuunnn!!!', effect.call('Ruby is fun!')
+  end
+
+  def test_loud
+    effect = Effects.loud(2)
+    assert_equal 'RUBY!! IS!! FUN!!!', effect.call('Ruby is fun!')
+
+    effect = Effects.loud(3)
+    assert_equal 'RUBY!!! IS!!! FUN!!!!', effect.call('Ruby is fun!')
+  end
+end

ruby-book/test/fizz_buzz_test.rb

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+require 'minitest/autorun'
+require './lib/fizz_buzz'
+
+class FizzBuzzTest < Minitest::Test
+  def test_fizz_buzz
+    assert_equal '1', fizz_buzz(1)
+    assert_equal '2', fizz_buzz(2)
+    assert_equal 'Fizz', fizz_buzz(3)
+    assert_equal '4', fizz_buzz(4)
+    assert_equal 'Buzz', fizz_buzz(5)
+    assert_equal 'Fizz', fizz_buzz(6)
+    assert_equal 'Fizz Buzz', fizz_buzz(15)
+  end
+end

ruby-book/test/gate_test.rb

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+require 'minitest/autorun'
+require './lib/gate'
+require './lib/ticket'
+
+class GateTest < Minitest::Test
+  def setup
+    @umeda = Gate.new(:umeda)
+    @juso = Gate.new(:juso)
+    @mikuni = Gate.new(:mikuni)
+  end
+
+  def test_umeda_to_juso
+    ticket = Ticket.new(150)
+    @umeda.enter(ticket)
+    assert @juso.exit(ticket)
+  end
+
+  def test_umeda_to_mikuni_when_fare_is_not_enough
+    ticket = Ticket.new(150)
+    @umeda.enter(ticket)
+    refute @mikuni.exit(ticket)
+  end
+
+  def test_umeda_to_mikuni_when_fare_is_enough
+    ticket = Ticket.new(190)
+    @umeda.enter(ticket)
+    assert @mikuni.exit(ticket)
+  end
+
+  def test_juso_to_mikuni
+    ticket = Ticket.new(150)
+    @juso.enter(ticket)
+    assert @mikuni.exit(ticket)
+  end
+end

ruby-book/test/rgb_test.rb

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+require 'minitest/autorun'
+require './lib/rgb'
+
+class RgbTest < Minitest::Test
+  def test_to_hex
+    assert_equal '#000000', to_hex(0, 0, 0)
+    assert_equal '#ffffff', to_hex(255, 255, 255)
+    assert_equal '#043c78', to_hex(4, 60, 120)
+  end
+
+  def test_to_ints
+    assert_equal [0, 0, 0], to_ints('#000000')
+    assert_equal [255, 255, 255], to_ints('#ffffff')
+    assert_equal [4, 60, 120], to_ints('#043c78')
+  end
+end

ruby-book/test/word_synth_test.rb

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+require 'minitest/autorun'
+require './lib/word_synth'
+require './lib/effects'
+
+class WordSynthTest < Minitest::Test
+  def test_play_without_effects
+    synth = WordSynth.new
+    assert_equal 'Ruby is fun!', synth.play('Ruby is fun!')
+  end
+
+  def test_play_with_reverse
+    synth = WordSynth.new
+    synth.add_effect(Effects.reverse)
+    assert_equal 'ybuR si !nuf', synth.play('Ruby is fun!')
+  end
+
+  def test_play_with_many_effects
+    synth = WordSynth.new
+    synth.add_effect(Effects.echo(2))
+    synth.add_effect(Effects.loud(3))
+    synth.add_effect(Effects.reverse)
+    assert_equal '!!!YYBBUURR !!!SSII !!!!!NNUUFF', synth.play('Ruby is fun!')
+  end
+end