Versioning

versioning.rb

module Versioned

	module V0
		def method_missing name
			puts "#{name} not found".red
		end
	end
	module V1
		def foo
			puts "foo 1"
		end
		def baz
			puts "baz 1"
		end
	end
	module V4
		def foo
			puts "foo 4"
		end
		def bar
			puts "bar 4"
		end
		# Undefine a method for this and all future versions
		def self.included mod
			mod.send :undef_method, :baz
		end
	end
	module V6
		def bar
			puts "bar 6"
		end
	end

	# return a custom module for the requested version
	def self.Version v

		# Determine all available versions
		versions = self.constants
			.sort
			.select { |name| /^V[0-9]+$/ === name } # Only include versioning constants
			.map { |name| name.to_s[1..-1].to_i } # Convert to integers for numeric comparison

		# Determine the effective version to use
		version = versions.reverse.find { |version| version <= v }

		# Compile the module (or use existing)
		Memoized.memoize version do
			parent = self
			Module.new do
				versions.select{ |version| version <= v}.each do |v|
					include parent.const_get(:"V#{v}")
				end
			end
		end

	end

end

# Attempt to load different versions
v1 = class One; include Versioned::Version 1; end.new
v2 = class Two; include Versioned::Version 5; end.new
v3 = class Three; include Versioned::Version 7; end.new

puts "V1"
v1.foo
v1.bar
v1.baz
puts v1.class.ancestors.inspect.cyan

puts ""
puts "V2"
v2.foo
v2.bar
v2.baz
puts v2.class.ancestors.inspect.cyan

puts ""
puts "V3"
v3.foo
v3.bar
v3.baz
puts v3.class.ancestors.inspect.cyan