Sample code for "Learning Haskell" tutorial

Video tutorial at:

• https://www.packtpub.com/gb/application-development/learning-haskell-programming
• https://www.linkedin.com/learning/learning-haskell-programming/the-course-overview?u=26889090
• https://learning.oreilly.com/videos/learning-haskell-programming/9781786465542