Showing posts from March, 2013

Implementing graph to tree conversion using Haskell

I began to become quite enamored with Haskell recently. At the very least, even if you can't use it on your current projects - because of the boss, because of legacy code, or because you just can't understand it well enough - you can always use it as an endless source of brain-teasers and puzzles. Also, since I'm recently switched to XMonad , at least some knowledge of haskell is a must. By the way, I'm extremely happy with XMonad, but that is a theme for a separate blog post :) Currently, I'm exploring various typeclasses ( State , Reader , Arrow , etc) and sometimes try to code some small snippets using them. For example, to practice using State monad, I implemented a method to extract a tree from graph using  DFS . Obviously, in such operation you need to maintain set of visited nodes somewhere, thus State seems to be a good fit. Here's the code in Haskell, and the same code in Scala (written in more "traditional" style): import qualifie