[439] | 1 | class Rational < Numeric
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| 2 | def inspect
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| 3 | "(#{to_s})"
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| 4 | end
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| 5 |
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| 6 | def to_s
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| 7 | "#{numerator}/#{denominator}"
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| 8 | end
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| 9 |
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| 10 | def *(rhs)
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| 11 | if rhs.is_a? Rational
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| 12 | Rational(numerator * rhs.numerator, denominator * rhs.denominator)
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| 13 | elsif rhs.is_a? Integer
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| 14 | Rational(numerator * rhs, denominator)
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| 15 | elsif rhs.is_a? Numeric
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| 16 | numerator * rhs / denominator
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| 17 | end
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| 18 | end
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| 19 |
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| 20 | def +(rhs)
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| 21 | if rhs.is_a? Rational
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| 22 | Rational(numerator * rhs.denominator + rhs.numerator * denominator, denominator * rhs.denominator)
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| 23 | elsif rhs.is_a? Integer
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| 24 | Rational(numerator + rhs * denominator, denominator)
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| 25 | elsif rhs.is_a? Numeric
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| 26 | (numerator + rhs * denominator) / denominator
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| 27 | end
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| 28 | end
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| 29 |
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| 30 | def -(rhs)
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| 31 | if rhs.is_a? Rational
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| 32 | Rational(numerator * rhs.denominator - rhs.numerator * denominator, denominator * rhs.denominator)
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| 33 | elsif rhs.is_a? Integer
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| 34 | Rational(numerator - rhs * denominator, denominator)
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| 35 | elsif rhs.is_a? Numeric
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| 36 | (numerator - rhs * denominator) / denominator
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| 37 | end
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| 38 | end
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| 39 |
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| 40 | def /(rhs)
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| 41 | if rhs.is_a? Rational
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| 42 | Rational(numerator * rhs.denominator, denominator * rhs.numerator)
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| 43 | elsif rhs.is_a? Integer
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| 44 | Rational(numerator, denominator * rhs)
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| 45 | elsif rhs.is_a? Numeric
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| 46 | numerator / rhs / denominator
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| 47 | end
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| 48 | end
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| 49 |
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| 50 | def <=>(rhs)
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| 51 | if rhs.is_a?(Integral)
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| 52 | return numerator <=> rhs if denominator == 1
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| 53 | rhs = Rational(rhs)
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| 54 | end
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| 55 |
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| 56 | case rhs
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| 57 | when Rational
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| 58 | (numerator * rhs.denominator - denominator * rhs.numerator) <=> 0
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| 59 | when Numeric
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| 60 | (rhs <=> self)&.-@
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| 61 | else
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| 62 | nil
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| 63 | end
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| 64 | end
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| 65 |
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| 66 | def ==(rhs)
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| 67 | return true if self.equal?(rhs)
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| 68 | if rhs.is_a?(Integral) && denominator == 1
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| 69 | return numerator == rhs
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| 70 | end
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| 71 | if rhs.is_a?(Rational)
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| 72 | numerator * rhs.denominator == denominator * rhs.numerator
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| 73 | else
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| 74 | rhs == self
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| 75 | end
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| 76 | end
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| 77 | end
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| 78 |
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| 79 | class Numeric
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| 80 | def to_r
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| 81 | Rational(self, 1)
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| 82 | end
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| 83 | end
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| 84 |
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| 85 | module Kernel
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| 86 | def Rational(numerator, denominator = 1)
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| 87 | a = numerator
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| 88 | b = denominator
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| 89 | a, b = b, a % b until b == 0
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| 90 | Rational._new(numerator.div(a), denominator.div(a))
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| 91 | end
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| 92 |
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| 93 | [:+, :-, :*, :/, :<=>, :==, :<, :<=, :>, :>=].each do |op|
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| 94 | Fixnum.instance_eval do
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| 95 | original_operator_name = "__original_operator_#{op}_rational"
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| 96 | alias_method original_operator_name, op
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| 97 | define_method op do |rhs|
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| 98 | if rhs.is_a? Rational
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| 99 | Rational(self).__send__(op, rhs)
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| 100 | else
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| 101 | __send__(original_operator_name, rhs)
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| 102 | end
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| 103 | end
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| 104 | end
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| 105 | Float.instance_eval do
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| 106 | original_operator_name = "__original_operator_#{op}_rational"
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| 107 | alias_method original_operator_name, op
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| 108 | define_method op do |rhs|
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| 109 | if rhs.is_a? Rational
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| 110 | rhs = rhs.to_f
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| 111 | end
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| 112 | __send__(original_operator_name, rhs)
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| 113 | end
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| 114 | end if Object.const_defined?(:Float)
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| 115 | end
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| 116 | end
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| 117 |
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