Metaprogramming: RUBY HOOK METHODS
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Metaprogramming: Ruby Hook Methods
Ruby comes with a bunch of hook methods that allow you to manipulate classes, modules and objects on the fly.
Here is a list of the most important hook methods:
Module#included Module#extended Module#prepended Class#inherited
included, extended and prepended modules
These hook methods are invoked whenever a module is included, extended or prepended in another module or class.
They work pretty similarly. So here we’re going to detail the included hook method
produces
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This hook method allows you to add methods and attributes according to the class/module that includes the module where the hook method is defined.
This mechanism is actually used by the ActiveSupport::Concern module.
The implementation is pretty similar for the Module#extended and Module#prepended hook methods.
Class#inherited
This hook method is called whenever a subclass of the class that implements the hook method is created
produces
Tenant is a kind of user
This hook method is pretty handy when you want to define a variable or a class_attribute at class definition for each children.
That’s exactly what the ActiveRecord::Core module does with the initialize_find_by_cache class method.
Conclusion
Hook methods can be pretty handy for class and module manipulation on the fly.
However, as they modify the module/class blueprint, it can provoke some undesired side effects like superclass method overriding, etc..
I’ll detail the BasicObject#method_missing hook method in another article.
Voilà !
Thank you for taking the time to read this post :-)
Feel free to :clap: and share this article if it has been useful for you.
Here is a link to my last article: Private & Protected: a matter of Message .
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