Accessing local variables from another binding in Ruby

Question

In Ruby, you can easily access local variables programmatically using local_variables and eval . I would really like to have metaprogramming access to these variables using one method call, for example

 # define a variable in this scope, such as x = 5 Foo.explore_locals # inside the Foo#explore_locals method, access x 

where Foo is some external module. The idea is to display and export local variables in a beautiful way.

What should be inside the explore_locals method? Is there any way to make this possible? If absolutely necessary, I think it could be

 Foo.explore_locals binding 

but it is much less elegant for the application that I mean.

Answer 1

It is a shame that there is no built-in way to get the caller’s binding. This trick seems to be the usual answer to this question.

However, there is another “trick” that existed for earlier versions of 1.8 Ruby called binding_of_caller . It looks like quix has ported it to 1.9. You can check this out:

https://github.com/quix/binding_of_caller

Answer 2

Here is an example (but this requires additional brackets {} , which I would rather avoid if possible):

 module Foo def self.explore_locals &block p block.binding.eval 'local_variables' end end local_1 = 3 Foo.explore_locals{} # shows [:local_1, :_]