ruby - Access to module instance variable -

i'm trying access instance variable in methods of module.

module filter   def self.included(target)     puts "included: #{@var}"     target.instance_variable_set(:@var, @var) # doesn't seem work   end    def self.var=(var)     @var = var   end    def self.var     @var   end    def hello     @var   end  end  f = filter f.var = "hello"  puts "set: #{f.var}"  class main   include filter end  m = main.new  puts "hello: #{m.hello}" 

it produces output:

ruby test2.rb set: hello included: hello hello:  

the last line "hello:" needs output "hello: hello". how initialize @var instance variable make happen?

as many-many others, confused term "instance variable" here. it's instance variable, right, it's not instance think about.

remember, in ruby object. classes themselves.

  def self.included(target)     puts "included: #{@var}"     target.instance_variable_set(:@var, @var) # doesn't seem work   end 

so here you're setting instance variable on target (which class, likely). yet you're trying read instance of target.

m = main.new  puts "hello: #{m.hello}" 

this variable is:

puts "the right hello: #{main.instance_variable_get(:@var)}" 

naturally, not possible set instance variable (in manner) on instance not yet exist! depending on you're after, different strategies can implemented. suggest ask another, more refined question.