Strictness meets data flow

Properties of programs can be formulated using various techniques: dataflow analysis, abstract interpretation and type-like inference systems. This paper reconstructs strictness analysis (establishing when function parameters are evaluated in a lazy language) as a dataflow analysis, by expressing the dataflow properties as an effect system. Strictness properties so expressed give a clearer operational understanding and enable a range of additional optimisations including implicational strictness. At first order strictness effects have the expected principality properties (best-property inference) and can be computed simply.status: publishe