Recursion schemes with Higherkindness
summary
Live refactor of list fold/unfold into generic recursion schemes using Scala, Cats and the Droste ideas, extracting a project functor (option of tuple), mapping recursion via Functor.map and then embedding back. Examples compute product of [1,20] = 200 and factorial(4) = 24 by composing anamorphism and catamorphism without allocating the intermediate list. Code compiles and runs; initial naive version is inefficient but the final Droste-style abstractions remove boilerplate and let the same algebra operate over different recursive structures.
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chapters (10)
- 0:00Introduction to talk
- 1:08Why recursion schemes matter
- 2:42FoldRight and Unfold basics
- 8:45Refactoring fold and unfold
- 13:10Abstracting over data structures
- 21:16Generic foldRight implementation
- 24:43Using foldRight generically
- 25:54Unfold to anamorphism
- 28:57Combining unfold and fold
- 30:43Conclusion and unconference
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