how to implement doubly linked lists

Question

Is it possible to have a doubly linked list in Haskell, and what\'s the ideal solution to implementing them? I\'m implementing a scene graph where every widget has a parent

Answer 1

Since you don't (usually) have OO-style objects in Haskell, it's weird to think of data being self-aware. It's important to note that you don't usually make use of aggregation in Haskell data types, favoring composition instead.

You might want to look into XMonad to see if their design matches your needs (the code is surprisingly readable).

You also might want to restructure your design so that you never need to look above you (for example, by passing children "callbacks").

You may also want to see if you can write a zipper for your whole graph.