Fix `Rational#==`

mrbgems/mruby-rational/mrbgem.rake

@@ -3,7 +3,6 @@ MRuby::Gem::Specification.new('mruby-rational') do |spec|
   spec.author  = 'mruby developers'
   spec.summary = 'Rational class'
 
-  spec.add_dependency 'mruby-metaprog', core: 'mruby-metaprog'
   spec.add_dependency 'mruby-object-ext', core: 'mruby-object-ext'
   spec.add_dependency 'mruby-numeric-ext', core: 'mruby-numeric-ext'
 end

mrbgems/mruby-rational/mrblib/rational.rb

 class Rational < Numeric
+  # Override #<, #<=, #>, #>= in Numeric
+  prepend Comparable
+
   def initialize(numerator = 0, denominator = 1)
     @numerator = numerator
     @denominator = denominator
@@ -66,6 +69,24 @@ class Rational < Numeric
     end
   end
 
+  def <=>(rhs)
+    case rhs
+    when Fixnum
+      return @numerator <=> rhs if @denominator == 1
+      rhs = Rational(rhs)
+    when Float
+      return to_f <=> rhs
+    end
+    case rhs
+    when Rational
+      (@numerator * rhs.denominator - @denominator * rhs.numerator) <=> 0
+    when Numeric
+      return rhs <=> self
+    else
+      nil
+    end
+  end
+
   def negative?
     numerator.negative?
   end
@@ -86,15 +107,15 @@ def Rational(numerator = 0, denominator = 1)
 end
 
 [Fixnum, Float].each do |cls|
-  [:+, :-, :*, :/, :==].each do |op|
+  [:+, :-, :*, :/, :<=>, :==, :<, :<=, :>, :>=].each do |op|
     cls.instance_exec do
       original_operator_name = "__original_operator_#{op}_rational"
       alias_method original_operator_name, op
       define_method op do |rhs|
         if rhs.is_a? Rational
-          Rational(self).send(op, rhs)
+          Rational(self).__send__(op, rhs)
         else
-          send(original_operator_name, rhs)
+          __send__(original_operator_name, rhs)
         end
       end
     end

mrbgems/mruby-rational/test/rational.rb

@@ -3,6 +3,16 @@ def assert_rational(real, exp)
   assert_float real.denominator, exp.denominator
 end
 
+def assert_equal_rational(exp, r1, r2)
+  if exp
+    assert_operator(r1, :==, r2)
+    assert_not_operator(r1, :!=, r2)
+  else
+    assert_not_operator(r1, :==, r2)
+    assert_operator(r1, :!=, r2)
+  end
+end
+
 assert 'Rational' do
   r = 5r
   assert_equal Rational, r.class
@@ -55,3 +65,38 @@ assert 'Rational#/' do
   assert_rational Rational(9, 8)  / 4,               Rational(9, 32)
   assert_float    Rational(20, 9) / 9.8,             0.22675736961451246
 end
+
+assert 'Rational#==, Rational#!=' do
+  assert_equal_rational(true, Rational(1,1), Rational(1))
+  assert_equal_rational(true, Rational(-1,1), -1r)
+  assert_equal_rational(true, Rational(13,4), 3.25)
+  assert_equal_rational(true, Rational(13,3.25), Rational(4,1))
+  assert_equal_rational(true, Rational(-3,-4), Rational(3,4))
+  assert_equal_rational(true, Rational(-4,5), Rational(4,-5))
+  assert_equal_rational(true, Rational(4,2), 2)
+  assert_equal_rational(true, Rational(-4,2), -2)
+  assert_equal_rational(true, Rational(4,-2), -2)
+  assert_equal_rational(true, Rational(4,2), 2.0)
+  assert_equal_rational(true, Rational(-4,2), -2.0)
+  assert_equal_rational(true, Rational(4,-2), -2.0)
+  assert_equal_rational(true, Rational(8,6), Rational(4,3))
+  assert_equal_rational(false, Rational(13,4), 3)
+  assert_equal_rational(false, Rational(13,4), 3.3)
+  assert_equal_rational(false, Rational(2,1), 1r)
+  assert_equal_rational(false, Rational(1), nil)
+  assert_equal_rational(false, Rational(1), '')
+end
+
+assert 'Fixnum#==(Rational), Fixnum#!=(Rational)' do
+  assert_equal_rational(true, 2, Rational(4,2))
+  assert_equal_rational(true, -2, Rational(-4,2))
+  assert_equal_rational(true, -2, Rational(4,-2))
+  assert_equal_rational(false, 3, Rational(13,4))
+end
+
+assert 'Float#==(Rational), Float#!=(Rational)' do
+  assert_equal_rational(true, 2.0, Rational(4,2))
+  assert_equal_rational(true, -2.0, Rational(-4,2))
+  assert_equal_rational(true, -2.0, Rational(4,-2))
+  assert_equal_rational(false, 3.3, Rational(13,4))
+end