From: Stefan Mueller <flcl@...>
Date: 2002-05-01T00:39:09+09:00
Subject: Override "initialize"

Hello

	I've been trying to find a way to prevent anyClass.new from
	calling initialize.

	I wondered how Marshal is able to create instances of classes even
	when initialize requires parameters that are not optional.

	The only way I could make it work seems rather cumbersome and
	prone to cause trouble. I'd really appreciate some opinions.

--------
module Instance
	def Instance.append_features(cl)
 		cl.instance_eval %{
			def instance
				Thread.critical = true
				begin                 
					alias_method :__origInit__, :initialize
					alias_method :initialize, :__newInit__
					return new
				ensure
					alias_method :__newInit__, :initialize
					alias_method :initialize, :__origInit__
					Thread.critical = false
				end
			end                 
		}
 		cl.module_eval %{
			def __newInit__; end
		}                       
	end
end

class Foo
	def initialize
		raise "prevent instance"
	end
	def foo
		"bar"
	end
end

class Foo
	include Instance
end

#Foo.new.foo  # => RuntimeError
        
puts Foo.instance.foo    # => "bar"




bye,
Stefan Mueller