Merging compositions of array skeletons in SaC

We describe a way out of this dilemma for array skeletons. In the functional array language SaC we internally represent individual array skeletons by one or more meta skeletons, called with-loops. The design of with-loops is carefully chosen to be versatile enough to cope with a large variety of skeletons, yet to be simple enough to allow for compilation into efficiently executable (parallel) code. Furthermore, with-loops are closed with respect to three tailor-made optimisation techniques, that systematically transform compositions of simple, computationally light-weight skeletons into few complex and computationally heavier-weight skeletons.