The space usage problem: An evaluation kit for graph reduction semantics

We describe a software tool for specifying operational sema ntics as a term-graph reduction system. The semantics are guaranteed to accurately model the asymptotic space and time usage of an implementation yet are abstract enough to support reasoning at the program level. Term graphs make explicit all the aspects of reduction relat ing to space usage as they naturally encode size and address information. The s emantics are constrained to be small-step, deterministic rules and each rew rite step uses bounded resources. The result is a system suitable for describing an d analysing the space behaviour of functional programming languages.