A practical introduction to category theory

on YouTube ↗32m

" summary

Introduces concrete patterns in Scala: Option as a short‑circuiting to‑do list pattern (monad) and Either that still short‑circuits, then shows how applicative functors let validations run in parallel so errors accumulate. Implements email/phone form validation, compares Option/Either behavior to Validated (no flatMap, so it combines errors) and uses the Cats library and its applicative operator to return either a Data case class or a list of error messages. Examples compile and behave as claimed.

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" chapters (6)

1. 0:00Introduction to the talk
2. 0:17My programming transition
3. 1:24Understanding composition
4. 18:21Limitations of types
5. 18:38Validation and applicatives
6. 27:02Conclusion and resources

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