ruby - Add variable to main -

for gem i'm working on need add variable main, preferably local variable, instance works well. i've been trying use object.instance_variable_set, have made no progress way. how can accomplish this?

clarification

i need set instance variable module within main.

here situation:

module mygem::submodule     def self.add_variable_to_main         object.instance_variable_set(:@var,"value")     end     def self.recieve_variable_from_main         object.instance_variable_get(:@var)     end     def self.store_block         @@block=&block     end     def self.call_block         add_variable_to_main         @@block.call         puts recieve_variable_from_main     end end  class object     include mygem::submodule end  store_block     @var = "var #{@var}" end  call_block 

i asked this question same problem, has additional details.

main object, objects can't have local variables. local variables belong lexical scopes, not objects.

you can assign instance variable in context of main:

@ivar = 42 

now main has instance variable @ivar value of 42.

object#instance_variable_set works same way:

instance_variable_set(:@ivar, 42) 

if not within context of main, can access top-level binding via global constant toplevel_binding, , main object via toplevel_binding.receiver, since main implicit receiver, i.e. self @ top-level:

module foo   toplevel_binding.receiver.instance_variable_set(:@ivar, 42) end  @ivar # => 42