A Pragmatic Introduction to Category Theories

on YouTube ↗40m

" summary

Demonstrates concrete code in Scala that builds Functor Applicative Monad implementations, implements a custom Maybe container and shows how map ap and flatMap behave, and uses scalacheck property tests to verify identity composition and associativity laws. Claims category-theory ideas simplify nullable values, error handling, parallel vs sequential operations and data validation, maps core abstractions to Cats, and shows the homemade library compiles and laws pass.

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" chapters (22)

1. 0:00Start
2. 6:04WHAT IS A CATEGORY?
3. 7:07COMPOSITION LAW
4. 7:31IDENTITY LAW
5. 7:54COMPOSITION - ASSOCIATIVITY
6. 10:24MONOID'S RULES
7. 11:08A PRACTICAL EXAMPLE
8. 13:31MONOID INSTANCES (2)
9. 14:11CATEGORY WITH 1+ OBJECT
10. 14:39CATEGORY IN A BOX
11. 16:56FUNCTOR'S RULES
12. 17:32LIFTING: CONTEXT VS CONTENT
13. 19:43FUNCTOR FOR MAYBE
14. 23:26APPLICATIVE FOR MAYBE
15. 24:15BOX IN A BOX
16. 26:09MONAD (AS FUNCTOR)
17. 27:26BOXES IN A SEQUENCE
18. 28:21FOR-COMPREHENSION
19. 29:45MONAD FOR MAYBE
20. 30:36FUNCTOR VS ENDOFUNCTOR
21. 34:00SUMMARY
22. 36:25WANNA KNOW MORE?

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