A Pragmatic Introduction to Category Theory

on YouTube ↗41m

" summary

Practical, non‑mathematical introduction that claims category concepts let codeers reason about composition and metadata by actually coding them: builds a small category‑theory library in Scala with tests written in ScalaCheck, implements Functor, Applicative and Monad typeclasses and law checks, models Maybe/Option, List and Int monoid instances, shows map/pure/ap/flatMap/flatten and for‑comprehension usage, and publishes the working workshop code on GitHub for direct reuse.

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" chapters (23)

1. 0:00Intro
2. 2:03I AM NOT A MATHEMATICIAN
3. 6:08WHAT IS A CATEGORY?
4. 7:13COMPOSITION LAW
5. 7:37IDENTITY LAW
6. 8:09COMPOSITION + ASSOCIATIVITY
7. 8:35CATEGORY'S RULES
8. 9:59CATEGORY WITH 1 OBJECT
9. 10:41MONOID'S RULES
10. 11:38A PRACTICAL EXAMPLE
11. 14:23MONOID INSTANCES (1)
12. 15:43CATEGORY IN A BOX
13. 16:17LIFTING: CONTEXT VS CONTENT
14. 17:44FUNCTOR'S RULES
15. 20:20FUNCTOR FOR MAYBE
16. 21:14BOX FUNCTION + BOX VALUES
17. 25:47APPLICATIVE FOR MAYBE
18. 27:10BOX IN A BOX
19. 29:20SCALACHECK FTW!
20. 30:32BOXES IN A SEQUENCE
21. 31:13FOR-COMPREHENSION
22. 32:55MONAD FOR MAYBE
23. 36:17SUMMARY

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