Module::Deprecatable

module-deprecatable.rb

class Module
  module Deprecatable
    def deprecated(name, options={})
      older = :"_deprecated_#{name}"
      alias_method older, name
      private older
      
      define_method name do |*args, &block|
        warn "#{__FILE__}:#{__LINE__}:WARN #{self.class}##{name} was deprecated, use new API #{self.class}##{options[:newer]}"
        __send__ older, *args, &block
      end
    end
  end

  include Deprecatable
end

class My
  def a
    puts 'HERE'
  end
  
  deprecated :a, newer: :b
end

My.new.a #=> module-deprecatable.rb:10:WARN My#a was deprecated, use new API My#b
         #=> "HERE"