Cats — A Fresh Look at Functional Programming in Scala

on YouTube ↗50m

" summary

Cats claims to fill gaps left by the Scala standard library for pure functional programming and already attracts real momentum: merged 100 pull requests in the first week and about 30 contributors in a few months. It ships concrete typeclasses and data types (SemigroupK, Xor, Validated, OneAnd/Kleisli), targets serializable instances for Spark, and deliberately omits niche bits like lenses (prefer Monocle) and a Task implementation. Development uses Kind Projector, Simulacrum, Discipline and tut so documentation is compiler‑verified and examples fail the build when broken.

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" chapters (15)

1. 0:00Intro
2. 0:24About me
3. 3:25Who is Involved
4. 9:54Moar Goals
5. 13:45Typeclasses (cats-core)
6. 18:27Renamed
7. 22:25Datatypes (cats-core)
8. 24:00Missing Datatypes
9. 29:21Out of scope
10. 32:06Dead Ideas
11. 36:25Project layout
12. 41:42Kind Projector
13. 44:43Discipline
14. 46:05Simulacrum
15. 47:54Compiler Verified Docs

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