While declarative programming languages are often considered to be applicable to “toy problems” only, we present an example
of a real-world programming task realized with a functional programming language. CondorCKD is a novel algebraic knowledge discovery algorithm completely implemented in Haskell. We give an overview of CondorCKD and describe our experiences gained during its development, including the implementation of a graphical user interface and
a novel approach to compute the cycles of an undirected graph.