bunch.rb in games_dice-0.4.0

- old
+ new
@@ -1,247 +1,241 @@
-# This class models a number of identical dice, which may be either GamesDice::Die or
-# GamesDice::ComplexDie objects.
-#
-# An object of this class represents a fixed number of indentical dice that may be rolled and their
-# values summed to make a total for the bunch.
-#
-# @example The ubiquitous '3d6'
-#  d = GamesDice::Bunch.new( :ndice => 3, :sides => 6 )
-#  d.roll # => 14
-#  d.result # => 14
-#  d.explain_result # => "2 + 6 + 6 = 14"
-#  d.max # => 18
-#
-# @example Roll 5d10, and keep the best 2
-#  d = GamesDice::Bunch.new( :ndice => 5, :sides => 10 , :keep_mode => :keep_best, :keep_number => 2 )
-#  d.roll # => 18
-#  d.result # => 18
-#  d.explain_result # => "4, 9, 2, 9, 1. Keep: 9 + 9 = 18"
-#
-
-class GamesDice::Bunch
-  # The constructor accepts parameters that are suitable for either GamesDice::Die or GamesDice::ComplexDie
-  # and decides which of those classes to instantiate.
-  # @param [Hash] options
-  # @option options [Integer] :ndice Number of dice in the bunch, *mandatory*
-  # @option options [Integer] :sides Number of sides on a single die in the bunch, *mandatory*
-  # @option options [String] :name Optional name for the bunch
-  # @option options [Array<GamesDice::RerollRule,Array>] :rerolls Optional rules that cause the die to roll again
-  # @option options [Array<GamesDice::MapRule,Array>] :maps Optional rules to convert a value into a final result for the die
-  # @option options [#rand] :prng Optional alternative source of randomness to Ruby's built-in #rand, passed to GamesDice::Die's constructor
-  # @option options [Symbol] :keep_mode Optional, either *:keep_best* or *:keep_worst*
-  # @option options [Integer] :keep_number Optional number of dice to keep when :keep_mode is not nil
-  # @return [GamesDice::Bunch]
-  def initialize( options )
-    name_number_sides_from_hash( options )
-    keep_mode_from_hash( options )
-
-    if options[:prng]
-      raise ":prng does not support the rand() method" if ! options[:prng].respond_to?(:rand)
-    end
-
-    if options[:rerolls] || options[:maps]
-      @single_die = GamesDice::ComplexDie.new( @sides, complex_die_params_from_hash( options ) )
-    else
-      @single_die = GamesDice::Die.new( @sides, options[:prng] )
-    end
-  end
-
-  # Name to help identify bunch
-  # @return [String]
-  attr_reader :name
-
-  # Number of dice to roll
-  # @return [Integer]
-  attr_reader :ndice
-
-  # Individual die from the bunch
-  # @return [GamesDice::Die,GamesDice::ComplexDie]
-  attr_reader :single_die
-
-  # Can be nil, :keep_best or :keep_worst
-  # @return [Symbol,nil]
-  attr_reader :keep_mode
-
-  # Number of "best" or "worst" results to select when #keep_mode is not nil.
-  # @return [Integer,nil]
-  attr_reader :keep_number
-
-  # Result of most-recent roll, or nil if no roll made yet.
-  # @return [Integer,nil]
-  attr_reader :result
-
-  # @!attribute [r] label
-  # Description that will be used in explanations with more than one bunch
-  # @return [String]
-  def label
-    return @name if @name != ''
-    return @ndice.to_s + 'd' + @sides.to_s
-  end
-
-  # @!attribute [r] rerolls
-  # Sequence of re-roll rules, or nil if re-rolls are not required.
-  # @return [Array<GamesDice::RerollRule>, nil]
-  def rerolls
-    @single_die.rerolls
-  end
-
-  # @!attribute [r] maps
-  # Sequence of map rules, or nil if mapping is not required.
-  # @return [Array<GamesDice::MapRule>, nil]
-  def maps
-    @single_die.maps
-  end
-
-  # @!attribute [r] result_details
-  # After calling #roll, this is an array of GamesDice::DieResult objects. There is one from each #single_die rolled,
-  # allowing inspection of how the result was obtained.
-  # @return [Array<GamesDice::DieResult>, nil] Sequence of GamesDice::DieResult objects.
-  def result_details
-    return nil unless @raw_result_details
-    @raw_result_details.map { |r| r.is_a?(Integer) ? GamesDice::DieResult.new(r) : r }
-  end
-
-  # @!attribute [r] min
-  # Minimum possible result from a call to #roll
-  # @return [Integer]
-  def min
-    n = @keep_mode ? [@keep_number,@ndice].min : @ndice
-    return n * @single_die.min
-  end
-
-  # @!attribute [r] max
-  # Maximum possible result from a call to #roll
-  # @return [Integer]
-  def max
-    n = @keep_mode ? [@keep_number,@ndice].min : @ndice
-    return n * @single_die.max
-  end
-
-  # Calculates the probability distribution for the bunch. When the bunch is composed of dice with
-  # open-ended re-roll rules, there are some arbitrary limits imposed to prevent large amounts of
-  # recursion.
-  # @return [GamesDice::Probabilities] Probability distribution of bunch.
-  def probabilities
-    return @probabilities if @probabilities
-
-    if @keep_mode && @ndice > @keep_number
-      @probabilities = @single_die.probabilities.repeat_n_sum_k( @ndice, @keep_number, @keep_mode )
-    else
-      @probabilities = @single_die.probabilities.repeat_sum( @ndice )
-    end
-
-    return @probabilities
-  end
-
-  # Simulates rolling the bunch of identical dice
-  # @return [Integer] Sum of all rolled dice, or sum of all keepers
-  def roll
-    @result = 0
-    @raw_result_details = []
-
-    @ndice.times do
-      @result += @single_die.roll
-      @raw_result_details << @single_die.result
-    end
-
-    if ! @keep_mode
-      return @result
-    end
-
-    use_dice = if @keep_mode && @keep_number < @ndice
-      case @keep_mode
-      when :keep_best then @raw_result_details.sort[-@keep_number..-1]
-      when :keep_worst then @raw_result_details.sort[0..(@keep_number-1)]
-      end
-    else
-      @raw_result_details
-    end
-
-    @result = use_dice.inject(0) { |so_far, die_result| so_far + die_result }
-  end
-
-  # @!attribute [r] explain_result
-  # Explanation of result, or nil if no call to #roll yet.
-  # @return [String,nil]
-  def explain_result
-    return nil unless @result
-
-    explanation = ''
-
-    # With #keep_mode, we may need to show unused and used dice separately
-    used_dice = result_details
-    unused_dice = []
-
-    # Pick highest numbers and their associated details
-    if @keep_mode && @keep_number < @ndice
-      full_dice = result_details.sort_by { |die_result| die_result.total }
-      case @keep_mode
-      when :keep_best then
-        used_dice = full_dice[-@keep_number..-1]
-        unused_dice = full_dice[0..full_dice.length-1-@keep_number]
-      when :keep_worst then
-        used_dice = full_dice[0..(@keep_number-1)]
-        unused_dice = full_dice[@keep_number..(full_dice.length-1)]
-      end
-    end
-
-    # Show unused dice (if any)
-    if @keep_mode || @single_die.maps
-      explanation += result_details.map do |die_result|
-        die_result.explain_value
-      end.join(', ')
-      if @keep_mode
-        separator = @single_die.maps ? ', ' : ' + '
-        explanation += ". Keep: " + used_dice.map do |die_result|
-          die_result.explain_total
-        end.join( separator )
-      end
-      if @single_die.maps
-        explanation += ". Successes: #{@result}"
-      end
-      explanation += " = #{@result}" if @keep_mode && ! @single_die.maps && @keep_number > 1
-    else
-      explanation += used_dice.map do |die_result|
-        die_result.explain_value
-      end.join(' + ')
-      explanation += " = #{@result}" if @ndice > 1
-    end
-
-    explanation
-  end
-
-  private
-
-  def name_number_sides_from_hash options
-    @name = options[:name].to_s
-    @ndice = Integer(options[:ndice])
-    raise ArgumentError, ":ndice must be 1 or more, but got #{@ndice}" unless @ndice > 0
-    @sides = Integer(options[:sides])
-    raise ArgumentError, ":sides must be 1 or more, but got #{@sides}" unless @sides > 0
-  end
-
-  def keep_mode_from_hash options
-    case options[:keep_mode]
-    when nil then
-      @keep_mode = nil
-    when :keep_best then
-      @keep_mode = :keep_best
-      @keep_number = Integer(options[:keep_number] || 1)
-    when :keep_worst then
-      @keep_mode = :keep_worst
-      @keep_number = Integer(options[:keep_number] || 1)
-    else
-      raise ArgumentError, ":keep_mode can be nil, :keep_best or :keep_worst. Got #{options[:keep_mode].inspect}"
-    end
-  end
-
-  def complex_die_params_from_hash options
-    cd_hash = Hash.new
-    [:maps,:rerolls].each do |k|
-      cd_hash[k] = options[k].clone if options[k]
-    end
-    # We deliberately do not clone this object, it will often be intended that it is shared
-    cd_hash[:prng] = options[:prng]
-    cd_hash
-  end
-end # class Bunch
+# frozen_string_literal: true
+
+module GamesDice
+  # This class models a number of identical dice, which may be either GamesDice::Die or
+  # GamesDice::ComplexDie objects.
+  #
+  # An object of this class represents a fixed number of indentical dice that may be rolled and their
+  # values summed to make a total for the bunch.
+  #
+  # @example The ubiquitous '3d6'
+  #  d = GamesDice::Bunch.new( :ndice => 3, :sides => 6 )
+  #  d.roll # => 14
+  #  d.result # => 14
+  #  d.explain_result # => "2 + 6 + 6 = 14"
+  #  d.max # => 18
+  #
+  # @example Roll 5d10, and keep the best 2
+  #  d = GamesDice::Bunch.new( :ndice => 5, :sides => 10 , :keep_mode => :keep_best, :keep_number => 2 )
+  #  d.roll # => 18
+  #  d.result # => 18
+  #  d.explain_result # => "4, 9, 2, 9, 1. Keep: 9 + 9 = 18"
+  #
+  class Bunch
+    # The constructor accepts parameters that are suitable for either GamesDice::Die or GamesDice::ComplexDie
+    # and decides which of those classes to instantiate.
+    # @param [Hash] options
+    # @option options [Integer] :ndice Number of dice in the bunch, *mandatory*
+    # @option options [Integer] :sides Number of sides on a single die in the bunch, *mandatory*
+    # @option options [String] :name Optional name for the bunch
+    # @option options [Array<GamesDice::RerollRule,Array>] :rerolls Optional rules that cause the die to roll again
+    # @option options [Array<GamesDice::MapRule,Array>] :maps Optional rules to convert a value into a final result for the die
+    # @option options [#rand] :prng Optional alternative source of randomness to Ruby's built-in #rand, passed to GamesDice::Die's constructor
+    # @option options [Symbol] :keep_mode Optional, either *:keep_best* or *:keep_worst*
+    # @option options [Integer] :keep_number Optional number of dice to keep when :keep_mode is not nil
+    # @return [GamesDice::Bunch]
+    def initialize(options)
+      name_number_sides_from_hash(options)
+      keep_mode_from_hash(options)
+
+      raise ':prng does not support the rand() method' if options[:prng] && !options[:prng].respond_to?(:rand)
+
+      @single_die = if options[:rerolls] || options[:maps]
+                      GamesDice::ComplexDie.new(@sides, complex_die_params_from_hash(options))
+                    else
+                      GamesDice::Die.new(@sides, options[:prng])
+                    end
+    end
+
+    # Name to help identify bunch
+    # @return [String]
+    attr_reader :name
+
+    # Number of dice to roll
+    # @return [Integer]
+    attr_reader :ndice
+
+    # Individual die from the bunch
+    # @return [GamesDice::Die,GamesDice::ComplexDie]
+    attr_reader :single_die
+
+    # Can be nil, :keep_best or :keep_worst
+    # @return [Symbol,nil]
+    attr_reader :keep_mode
+
+    # Number of "best" or "worst" results to select when #keep_mode is not nil.
+    # @return [Integer,nil]
+    attr_reader :keep_number
+
+    # Result of most-recent roll, or nil if no roll made yet.
+    # @return [Integer,nil]
+    attr_reader :result
+
+    # @!attribute [r] label
+    # Description that will be used in explanations with more than one bunch
+    # @return [String]
+    def label
+      return @name if @name != ''
+
+      "#{@ndice}d#{@sides}"
+    end
+
+    # @!attribute [r] rerolls
+    # Sequence of re-roll rules, or nil if re-rolls are not required.
+    # @return [Array<GamesDice::RerollRule>, nil]
+    def rerolls
+      @single_die.rerolls
+    end
+
+    # @!attribute [r] maps
+    # Sequence of map rules, or nil if mapping is not required.
+    # @return [Array<GamesDice::MapRule>, nil]
+    def maps
+      @single_die.maps
+    end
+
+    # @!attribute [r] result_details
+    # After calling #roll, this is an array of GamesDice::DieResult objects. There is one from each #single_die rolled,
+    # allowing inspection of how the result was obtained.
+    # @return [Array<GamesDice::DieResult>, nil] Sequence of GamesDice::DieResult objects.
+    def result_details
+      return nil unless @raw_result_details
+
+      @raw_result_details.map { |r| r.is_a?(Integer) ? GamesDice::DieResult.new(r) : r }
+    end
+
+    # @!attribute [r] min
+    # Minimum possible result from a call to #roll
+    # @return [Integer]
+    def min
+      n = @keep_mode ? [@keep_number, @ndice].min : @ndice
+      n * @single_die.min
+    end
+
+    # @!attribute [r] max
+    # Maximum possible result from a call to #roll
+    # @return [Integer]
+    def max
+      n = @keep_mode ? [@keep_number, @ndice].min : @ndice
+      n * @single_die.max
+    end
+
+    # Calculates the probability distribution for the bunch. When the bunch is composed of dice with
+    # open-ended re-roll rules, there are some arbitrary limits imposed to prevent large amounts of
+    # recursion.
+    # @return [GamesDice::Probabilities] Probability distribution of bunch.
+    def probabilities
+      return @probabilities if @probabilities
+
+      @probabilities = if @keep_mode && @ndice > @keep_number
+                         @single_die.probabilities.repeat_n_sum_k(@ndice, @keep_number, @keep_mode)
+                       else
+                         @single_die.probabilities.repeat_sum(@ndice)
+                       end
+
+      @probabilities
+    end
+
+    # Simulates rolling the bunch of identical dice
+    # @return [Integer] Sum of all rolled dice, or sum of all keepers
+    def roll
+      @result = 0
+      @raw_result_details = []
+
+      @ndice.times do
+        @result += @single_die.roll
+        @raw_result_details << @single_die.result
+      end
+
+      return @result unless @keep_mode
+
+      use_dice = if @keep_mode && @keep_number < @ndice
+                   case @keep_mode
+                   when :keep_best then @raw_result_details.sort[-@keep_number..]
+                   when :keep_worst then @raw_result_details.sort[0..(@keep_number - 1)]
+                   end
+                 else
+                   @raw_result_details
+                 end
+
+      @result = use_dice.inject(0) { |so_far, die_result| so_far + die_result }
+    end
+
+    # @!attribute [r] explain_result
+    # Explanation of result, or nil if no call to #roll yet.
+    # @return [String,nil]
+    def explain_result
+      return nil unless @result
+
+      explanation = ''
+
+      # With #keep_mode, we may need to show unused and used dice separately
+      used_dice = result_details
+      unused_dice = []
+
+      # Pick highest numbers and their associated details
+      if @keep_mode && @keep_number < @ndice
+        full_dice = result_details.sort_by(&:total)
+        case @keep_mode
+        when :keep_best
+          used_dice = full_dice[-@keep_number..]
+          unused_dice = full_dice[0..full_dice.length - 1 - @keep_number]
+        when :keep_worst
+          used_dice = full_dice[0..(@keep_number - 1)]
+          unused_dice = full_dice[@keep_number..(full_dice.length - 1)]
+        end
+      end
+
+      # Show unused dice (if any)
+      if @keep_mode || @single_die.maps
+        explanation += result_details.map(&:explain_value).join(', ')
+        if @keep_mode
+          separator = @single_die.maps ? ', ' : ' + '
+          explanation += ". Keep: #{used_dice.map(&:explain_total).join(separator)}"
+        end
+        explanation += ". Successes: #{@result}" if @single_die.maps
+        explanation += " = #{@result}" if @keep_mode && !@single_die.maps && @keep_number > 1
+      else
+        explanation += used_dice.map(&:explain_value).join(' + ')
+        explanation += " = #{@result}" if @ndice > 1
+      end
+
+      explanation
+    end
+
+    private
+
+    def name_number_sides_from_hash(options)
+      @name = options[:name].to_s
+      @ndice = Integer(options[:ndice])
+      raise ArgumentError, ":ndice must be 1 or more, but got #{@ndice}" unless @ndice.positive?
+
+      @sides = Integer(options[:sides])
+      raise ArgumentError, ":sides must be 1 or more, but got #{@sides}" unless @sides.positive?
+    end
+
+    def keep_mode_from_hash(options)
+      case options[:keep_mode]
+      when nil
+        @keep_mode = nil
+      when :keep_best
+        @keep_mode = :keep_best
+        @keep_number = Integer(options[:keep_number] || 1)
+      when :keep_worst
+        @keep_mode = :keep_worst
+        @keep_number = Integer(options[:keep_number] || 1)
+      else
+        raise ArgumentError, ":keep_mode can be nil, :keep_best or :keep_worst. Got #{options[:keep_mode].inspect}"
+      end
+    end
+
+    def complex_die_params_from_hash(options)
+      cd_hash = {}
+      %i[maps rerolls].each do |k|
+        cd_hash[k] = options[k].clone if options[k]
+      end
+      # We deliberately do not clone this object, it will often be intended that it is shared
+      cd_hash[:prng] = options[:prng]
+      cd_hash
+    end
+  end
+end