requal.rb

a = Object.new
b = Object.new
c = "foo"
b.instance_eval{@foo = "bar"}
print "a = ";p a
print "b = ";p b 
print "c = ";p c
puts "EQUAL1:"
print "a == a     =>";p a == a
print "b == b     =>";p b == b
print "c == c     =>";p c == c
print 'c == "foo" =>';p c == "foo"
print "c == a     =>";p c == a
print "a == b     =>";p a == b
print "b == c     =>";p b == c
print "a == c     =>";p a == c
print "b == a     =>";p b == a
print "c == b     =>";p c == b
print 'c == 1     =>';p c == 1

ObjectSpace.each_object(Module) {|m|
  m.module_eval{undef :equal?;undef :==} if m.method_defined?(:equal?)
  m.module_eval{def equal?(o);true;end}
  m.module_eval{def ==(o);true;end}
}
class Object
  def equal?(other)
    true
  end
  def ==(other)
    true
  end
end
puts "EQUAL2:"
print "a == a     =>";p a == a
print "b == b     =>";p b == b
print "c == c     =>";p c == c
print 'c == "foo" =>';p c == "foo"
print "c == a     =>";p c == a
print "a == b     =>";p a == b
print "b == c     =>";p b == c
print "a == c     =>";p a == c
print "b == a     =>";p b == a
print "c == b     =>";p c == b
print 'c == 1     =>';p c == 1