Theorem proving for functional programmers Sparkle: a functional theorem prover

Sparkle is a new theorem prover written and specialized in the functional programming language Clean. It is in the first place intended to be used by programmers on small parts of Clean-programs, combining theorem proving and programming into one process. It should of course also be usable by logicians interested in proving properties of larger programs. This paper presents an example proof about a small Clean-program. It will be shown that building this proof in Sparkle is very easy and will require little effort from Clean-programmers. The most important features of Sparkle will be illustrated. Two features in particular are helpful for programmers. Firstly, Sparkle is integrated in Clean and has a semantics based on lazy graph-rewriting. This allows the reasoning to take place on the program itself, rather than on a translated version which uses different concepts. Secondly, Sparkle supports automated reasoning. Trivial goals will automatically be discarded and suggestions will be given on more difficult goals.