first commit

nghttp2/third-party/mruby/mrbgems/mruby-rational/mrblib/rational.rb

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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