Programming Ruby 3.3

Looking at Classes

Knowing about objects is one aspect of reflection, but to get the whole picture, you also need to be able to look at classes—and the methods and constants that they contain.

Looking at the class hierarchy is easy. You can get the parent of any particular class using Class#superclass and its children using Class#subclasses. For classes and modules, the Module#ancestors method lists both superclasses and mixed-in modules:

ospace/relatives.rb

klass = Integer
print "Inheritance chain: "
begin
  print klass
  klass = klass.superclass
  print " < " if klass
end while klass
puts
p "Ancestors: #{Integer.ancestors}"
p "Subclasses: #{Integer.subclasses}"

Produces:

Inheritance chain: Integer < ...