DDT: A declarative debugging tool for functional-logic languages

Abstract

We present a graphical tool for the declarative debugging of wrong answers in functional-logic languages. The tool, integrated in the system TOY, can be used to navigate a computation tree corresponding to some erroneous computation. During the navigation the users can either follow a fixed strategy or move freely providing information about the validity of the nodes as they like. We show by means of examples how this flexibility can reduce both the number and the complexity of the questions that the user must consider w.r.t. the usual top-down navigation strategy. Moreover, the tool includes some extra features that can be used to automatically simplify the computation trees. © Springer-Verlag 2004.