class_macro.rb

# ==================
# Spell: Class Macro
# ==================

# Use a class method in a class definition.

class C; end

class << C
  def my_macro(arg)
    "my_macro(#{arg}) called"
  end
end

class C
  my_macro :x # => "my_macro(x) called"
end

# For more information: http://www.pragprog.com/titles/ppmetr/metaprogramming-ruby