The Shape of Shapeless (Part 2)
summary
Walks through concrete techniques to derive code with Shapeless: defines a lexicographic compareHList, exposes output types with the ox pattern (refinement aliases), uses Scala implicits and HLists to derive an Ordering for case classes (Point2D example) and for recursive binary trees, and shows when derivation diverges and how lazy boxes break recursive implicit loops. Demonstrates working derivation, lists where it fails, and the specific fixes and tradeoffs (macros for generic instances, runtime/compile fragility).
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chapters (11)
- 0:00Start
- 3:49Implicit Resolution
- 8:07Refinement Types
- 8:46Refinement Test
- 11:02Ox Pattern
- 19:43Exercises
- 20:40Generic Programming
- 21:462d Binary Trees
- 26:54Co-Product
- 37:09Implicit Cases
- 51:46The Value of Shapeless
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