ダイス目の偶奇のみを見るテーブルを実装

lib/bcdice/dice_table.rb

@@ -8,6 +8,7 @@
 require "bcdice/dice_table/d66_parity_table"
 require "bcdice/dice_table/d66_range_table"
 require "bcdice/dice_table/d66_table"
+require "bcdice/dice_table/parity_table"
 require "bcdice/dice_table/range_table"
 require "bcdice/dice_table/sai_fic_skill_table"
 require "bcdice/dice_table/table"

lib/bcdice/dice_table/parity_table.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module BCDice
+  module DiceTable
+    # 出目の偶奇による場合分け機能をもつ表
+    class ParityTable
+      # @param [String] name 表の名前
+      # @param [String] type 項目を選ぶときのダイスロールの方法 '1D6'など
+      # @param [String] odd ダイス目が奇数のときの結果
+      # @param [String] even ダイス目が偶数のときの結果
+      def initialize(name, type, odd, even)
+        @name = name
+        @odd = odd.freeze
+        @even = even.freeze
+
+        m = /(\d+)D(\d+)/i.match(type)
+        unless m
+          raise ArgumentError, "Unexpected table type: #{type}"
+        end
+
+        @times = m[1].to_i
+        @sides = m[2].to_i
+      end
+
+      # 表を振る
+      # @param [BCDice] bcdice ランダマイザ
+      # @return [String] 結果
+      def roll(bcdice)
+        value = bcdice.roll_sum(@times, @sides)
+        return RollResult.new(@name, value, value.odd? ? @odd : @even)
+      end
+    end
+  end
+end

test/test_parity_table.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require "test/unit"
+require "bcdice"
+require "bcdice/dice_table/parity_table"
+
+require_relative "randomizer_mock"
+
+class TestParityTable < Test::Unit::TestCase
+  # ダイス目の偶奇のみを見る
+  def test_parity
+    table = BCDice::DiceTable::ParityTable.new(
+      "テスト",
+      "1D6",
+      "odd",
+      "even"
+    )
+
+    randomizer = RandomizerMock.new([[1, 6]])
+    assert_equal("テスト(1) ＞ odd", table.roll(randomizer).to_s)
+
+    randomizer = RandomizerMock.new([[2, 6]])
+    assert_equal("テスト(2) ＞ even", table.roll(randomizer).to_s)
+
+    randomizer = RandomizerMock.new([[3, 6]])
+    assert_equal("テスト(3) ＞ odd", table.roll(randomizer).to_s)
+
+    randomizer = RandomizerMock.new([[4, 6]])
+    assert_equal("テスト(4) ＞ even", table.roll(randomizer).to_s)
+
+    randomizer = RandomizerMock.new([[5, 6]])
+    assert_equal("テスト(5) ＞ odd", table.roll(randomizer).to_s)
+
+    randomizer = RandomizerMock.new([[6, 6]])
+    assert_equal("テスト(6) ＞ even", table.roll(randomizer).to_s)
+  end
+end