Metaprogramming: Unraveling the Magic

on YouTube ↗18m

" summary

Live code shows how Rails-style metaprogramming actually generates methods at runtime: reopening String to implement a working titleize that capitalizes words, using define_method to create enum predicates that return true for admin, and using public_send to dispatch add/subtract calls dynamically. Demos expose singleton methods stored in an eigenclass (class methods via metaclass), instance-level access via instance_eval, and class-level changes via class_eval (Rails uses this for concerns and scopes); undefined-method examples produce the expected errors.

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" chapters (17)

1. 0:00Introduction and welcome
2. 1:59What is metaprogramming
3. 3:03Metaprogramming in Ruby
4. 4:08Open classes and monkey patching
5. 6:19Method missing and dynamic methods
6. 7:49Dynamic method dispatch
7. 9:26Using send method
8. 10:09Singleton methods
9. 11:34Metaclasses and n-classes
10. 12:22Defining class methods
11. 12:43Mimic methods like attr_accessor
12. 13:25Hook methods and lifecycle
13. 14:56Accessing instance variables
14. 15:44Class eval and open classes
15. 16:58Cherry picking methods
16. 17:46Method missing as a fallback
17. 18:12Closing and thanks

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