How I Teach Functional Programming

J. Waldmann, March 9, 2017; update July 3

I teach a required course “advanced programming techniques” that contains an introduction to Functional Programming (using Haskell) as well as on overview of techniques from functional programming in other paradigms (like object orientation - OO) and languages (like C#, Java).

In this course, I present (in this order)

  • Data (terms, trees, algebraic data types, data)
  • (first order) Programs (term rewriting, pattern matching, case)
  • Polymorphism (type constructors)
  • (higher order) Programs (lambda calculus, lambda expressions)
  • Recursion Schemes (folds - for trees, lists (yes), Peano numbers)
  • OO simulation of algebraic data types (the “composite” design pattern)
  • OO simulation of recursion schemes (the “visitor” design pattern)
  • Restricted Polymorphism (Haskell type classes vs. Java interfaces)
  • Lazy evaluation (streams) and its OO simulation (the “iterator” design pattern)
  • Higher order functions for stream processing (in Haskell, LINQ, java.util.streams)
  • functional reactive programming (vs. the OO “observer” pattern) (since 2017)

Students solve online exercises (try them here) via the Leipzig autotool system.

The slides for the course are here: 2016, 2017.

(Related: on avoiding built-in data types, in particular, lists.)

This course fits in our curriculum for Bachelor students in computer science, which contains these courses (among others)

  • 1st term: introduction to discrete mathematics and logics, to computation and programming
  • 2nd term: algorithms and data structures
  • 3rd term: software engineering
  • 4th term: advanced programming techniques (my course), software engineering project work
  • 5th term: language concepts for parallel and concurrent programming

Here I only mentioned courses with a direct relation to programming. Here is the full curriculum.