Type classes explained

Polymorphism via inheritance

Polymorphism via type classes

OOP approach consolidates data and related functions in one place— class definition. “Type classes” go with a different approach — entities representing data are decoupled from entities responsible for implementation.

  1. Code duplication — if we want to change Circle we would also need to change CircleShape.
  2. To call areaOf we need to pass instance of CircleShape, not the Circle itself.



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Oleksii Avramenko

Oleksii Avramenko

Into Scala, Haskell and functional programming