Ruby was designed to make programmers happy, and there are lots of little things in it that contribute to achieving this goal. What amazes me is that, even after using it for years, one can still find some of these little things here and there, that you did not know about. Today was one of those days for me.

It turns out that the syntax for specifying class inheritance in Ruby, bares some resemblance to the syntax for testing wether two classes are related by inheritance. The following code snippet says it all:

class Person < ActiveRecord::Base
end

if Person < ActiveRecord::Base
  puts "The class 'Person' is a subclass of ActiveRecord::Base"
else
  puts "The class 'Person' is NOT a subclass of ActiveRecord::Base"
end

Brilliant, isn’t it?

It turns out you can use all four inequality operators, and you’ll get the expected result. Given a class A with a subclass B, the following code shows how it works:

B < A    # true
B > A    # false
B <= A   # true
B >= A   # false
A >= A   # true
A > A    # false

This is the kind of little things that make me a happy programmer ;)