Class: CARPS::Dice::D

Inherits:
Object
  • Object
show all
Defined in:
lib/carps/mod/dice.rb

Overview

A dice

Note that the methods here - including +, *, etc - update the dice’s internal state, and do not return a new dice.

Instance Method Summary collapse

Constructor Details

#initialize(i) ⇒ D

Create the dice from an integer, the number of sides

The dice will have sides numbered from 1 to i.



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# File 'lib/carps/mod/dice.rb', line 47

def initialize i
   @rolls = {}
   @weights = {}
   fair_weight = 1.0 / i
   i.times do |n|
      n = n + 1
      @rolls[n] = n
      @weights[n] = 1.0 / i
   end
end

Instance Method Details

#*(other) ⇒ Object

Multiply by a number or another dice



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# File 'lib/carps/mod/dice.rb', line 134

def * other
   if is_num other
      mul_num other
   else
      mul_dice other
   end
end

#+(other) ⇒ Object

Add a number or another dice



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# File 'lib/carps/mod/dice.rb', line 116

def + other
   if is_num other
      add_num other
   else
      add_dice other
   end
end

#-(other) ⇒ Object

Subtract a number or another dice



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# File 'lib/carps/mod/dice.rb', line 125

def - other
   if is_num other
      add_num (other * -1)
   else
      subtract_dice other
   end
end

#/(other) ⇒ Object

Divide by a number or another dice



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# File 'lib/carps/mod/dice.rb', line 143

def / other
   if is_num other
      div_num other
   else
      div_dice other
   end
end

#in_range(range, output) ⇒ Object

Directly inspect the range and supply a number or a dice as output, if the result is in that range



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# File 'lib/carps/mod/dice.rb', line 152

def in_range range, output
   if is_num output
      in_range_int range, output
   else
      in_range_dice range, output
   end
end

#is(compare, other, output) ⇒ Object

If the result matches a binary comparison, then return this result

compare is one of :<, :<=, :==, :>, :>=

other is an integer to compare with



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# File 'lib/carps/mod/dice.rb', line 165

def is compare, other, output
   cmp = Dice::comparison_to_proc compare, other

   rng = find_range cmp
   if rng
      in_range rng, output
   end
end

#odds ⇒ Object

Output the odds

That is, a hash of results to the probabalistic weights of the possible results.



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# File 'lib/carps/mod/dice.rb', line 92

def odds
   od = {}
   @weights.each do |roll, weight|
      result = @rolls[roll]
      if od.include? result
         od[result] = od[result] + weight
      else
         od[result] = weight
      end
   end
   od
end

#roll ⇒ Object

Roll the dice

Raises:

  • (StandardError) 


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# File 'lib/carps/mod/dice.rb', line 59

def roll
   od = []
   results = odds.to_a
   current = 0
   # Build up range arrays corresponding to probabalistic weights
   until results.empty?
      # Manually insert a 1 at the end to make this numerically stable
      last = false
      if results.length == 1
         last = true
      end
      result, weight = results.shift
      if last
         od.push [current..1, result]
      else
         new_top = current + weight
         od.push [current..new_top, result]
         current = new_top
      end
   end
   # Find the appropriate action
   r = rand
   od.each do |range, result|
      if range.include? r
         return result
      end
   end
   raise StandardError, "BUG: Dice has no result."
end

#rolls ⇒ Object

Output the roll table



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# File 'lib/carps/mod/dice.rb', line 111

def rolls
   @rolls
end

#weights ⇒ Object

Output the weights table



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# File 'lib/carps/mod/dice.rb', line 106

def weights
   @weights
end