Introduction

Resursion is an important technique in programming, especially in functional programming.

Simple examples:

  1. fact :: Integer -> Integer
  2. fact 0 = 1
  3. fact n = n * fact (n - 1)
  5. > fact 10
  6. 3628800
  7. > fact 5
  8. 120
  10. fib :: Integer -> Integer
  11. fib 0 = 1
  12. fib 1 = 1
  13. fib n = fib (n - 1) + fib (n - 2)
  15. > fib 10
  16. 89
  17. > fib 5
  18. 8