Scope Gates in Ruby: Part II
In this article, we’re going to explore the following topics:
- module scope
- nesting and scopes
First, feel free to have a look to the
Scope Gates in Ruby: Part I.
Module Scope
When we use the module keyword:
- The value of
selfchanges - The content of the module is embedded in an isolated scope
Let’s have a look at the following example
Here we can see that in our module self has a different value — it refers to the Commentable module.
Also, we don’t have access to variables and methods defined outside the module.
Note that we have access to instance variables in methods for the same reasons described in Part I.
Nesting and scopes
When we nest a module or a class in another module then:
- The value of
selfchanges - The content of the nested module is embedded in an isolated scope
- The nested module can’t access local variables from higher scopes
- The nested module can’t access instance variables defined in the nesting scope
Here, the value of self is First in the nesting module and First::Second in the nested module.
Also, we can see the First::Second module can’t access the @instance_variable variable defined in the First module.
Indeed, @instance_variable equals to nil because it’s a freshly defined instance variable in the First::Second module
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