Polymorphism in Scala

on YouTube ↗41m

" summary

Compares four polymorphism techniques in Scala—subtyping, generics (parametric polymorphism), implicits/typeclasses, and ad hoc pattern-based dispatch—by implementing a reusable Printer typeclass using implicits and companion-object instance discovery. Shows how the Scala compiler selects implementations, how variance and higher-kinded type parameters affect APIs, which approaches require boilerplate, and when instance forwarding or default instances reduce code; includes small runnable examples and a few failure cases that reveal surprising loss of type information.

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" chapters (12)

1. 0:00Polymorphism in Scala
2. 4:18Function parameter inclusion
3. 8:31Parameter combinations
4. 13:19Firewall details
5. 16:33Variance in containers
6. 20:54Modifying classes
7. 24:09Interface design
8. 27:51Object lifecycle
9. 30:56Parameter context
10. 34:45External interfaces
11. 37:51Boilerplate
12. 40:57Summary

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