[Haskell-beginners] Learning Haskell with the help of trees

Hi, I am beginning to learn Haskell, and I decided to try to implement a tree. Its code is available at https://gist.github.com/anonymous/dd3eaa8bc36025d7751c I would need some help with implementing the delete element procedure. I have a feeling I am doing something very unhaskelly there. Also, when deleting a node having two children, how do I run two actions (swap the values and delete the successor)? Also, I would be delighted if you could take a look on the style and similar aspects, as they are best addressed at the beginning. Thanks, Michal