Lesson 1: Introduction to Mapping

  • Maybe a
  • Maybe map
  • Higher kindedness
  • Either map
  • Naming the class
  • Other functors
  • List map
  • Coming up

Applying functions to values to produce new values is the most fundamental act of programming there is, and it’s what a lambda calculus like Haskell is centered around. However, in any nontrivial Haskell program, you find yourself dealing with values that are embedded or contained in some other type. You still need a way to apply functions to those values, despite the fact that they are hidden within some other type structure. In this lesson, we’ll look at an example, write a function that solves that problem for us, and then begin discussing how to generalize it.

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