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class Rational < Numeric
def inspect
"(#{to_s})"
end
def to_s
"#{numerator}/#{denominator}"
end
def *(rhs)
if rhs.is_a? Rational
Rational(numerator * rhs.numerator, denominator * rhs.denominator)
elsif rhs.is_a? Integer
Rational(numerator * rhs, denominator)
elsif rhs.is_a? Numeric
numerator * rhs / denominator
end
end
def +(rhs)
if rhs.is_a? Rational
Rational(numerator * rhs.denominator + rhs.numerator * denominator, denominator * rhs.denominator)
elsif rhs.is_a? Integer
Rational(numerator + rhs * denominator, denominator)
elsif rhs.is_a? Numeric
(numerator + rhs * denominator) / denominator
end
end
def -(rhs)
if rhs.is_a? Rational
Rational(numerator * rhs.denominator - rhs.numerator * denominator, denominator * rhs.denominator)
elsif rhs.is_a? Integer
Rational(numerator - rhs * denominator, denominator)
elsif rhs.is_a? Numeric
(numerator - rhs * denominator) / denominator
end
end
def /(rhs)
if rhs.is_a? Rational
Rational(numerator * rhs.denominator, denominator * rhs.numerator)
elsif rhs.is_a? Integer
Rational(numerator, denominator * rhs)
elsif rhs.is_a? Numeric
numerator / rhs / denominator
end
end
def <=>(rhs)
if rhs.is_a?(Integral)
return numerator <=> rhs if denominator == 1
rhs = Rational(rhs)
end
case rhs
when Rational
(numerator * rhs.denominator - denominator * rhs.numerator) <=> 0
when Numeric
(rhs <=> self)&.-@
else
nil
end
end
def ==(rhs)
return true if self.equal?(rhs)
if rhs.is_a?(Integral) && denominator == 1
return numerator == rhs
end
if rhs.is_a?(Rational)
numerator * rhs.denominator == denominator * rhs.numerator
else
rhs == self
end
end
end
class Numeric
def to_r
Rational(self, 1)
end
end
module Kernel
def Rational(numerator, denominator = 1)
a = numerator
b = denominator
a, b = b, a % b until b == 0
Rational._new(numerator.div(a), denominator.div(a))
end
[:+, :-, :*, :/, :<=>, :==, :<, :<=, :>, :>=].each do |op|
original_operator_name = :"__original_operator_#{op}_rational"
Fixnum.instance_eval do
alias_method original_operator_name, op
define_method op do |rhs|
if rhs.is_a? Rational
Rational(self).__send__(op, rhs)
else
__send__(original_operator_name, rhs)
end
end
end
Float.instance_eval do
alias_method original_operator_name, op
define_method op do |rhs|
if rhs.is_a? Rational
rhs = rhs.to_f
end
__send__(original_operator_name, rhs)
end
end if Object.const_defined?(:Float)
end
end
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