Sloth – a Tool for Checking Minimal-Strictness

We present a light-weight tool called Sloth which assists programmers in identifying unnecessarily strict first order functions. Sloth reports counterexamples in form of a partial value, the corresponding result of the tested function and a recommended result. We present examples where the hints reported by Sloth can be used to improve a function with respect to memory behaviour, non-termination, and performance in the context of functional-logic programming. Furthermore we give an example-driven introduction into the basics of the implementation of Sloth. To improve the results in comparison to an existing approach we use additional constraints to assure that Sloth s suggestions are implementable without employing parallelism.