Monad Transformers for the Easily Confused

on YouTube ↗50m

" summary

Claims that monad transformers let different effects be composed are demonstrated with concrete Haskell code, a tiny Stack repo, and the transformers package ecosystem fact (over 2,500 Stackage packages). The talk shows how to implement and read bind via runIdentityT and join, how to lift IO into MaybeT with lift and runMaybeT, and how stacking order changes semantics. Examples build toward a working functional web app using persistence/esqueleto and SQLite, with runnable code and compilation notes.

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" chapters (20)

1. 0:00Intro
2. 0:30Code
3. 2:12Summary
4. 3:54Functors
5. 5:21Pure
6. 6:48Interchange
7. 9:01Dollar
8. 9:53Composition
9. 11:53Three Monad Laws
10. 13:14Examples
11. 15:40Operators
12. 16:44Functor
13. 20:16Join
14. 23:02Identity Team
15. 26:59Ship
16. 29:18Identity
17. 31:01IO String
18. 32:18Lift
19. 33:33IO
20. 39:37Identity TM

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