On the time required for reference count management in retention block-structured languages. Part 2

Abstract

In this paper, two implementations of generalized block-structured languages are presented and compared for time requirements. One implementation, the Lifetime Stack Model, implements the deletion strategy with lifetime checks; the other, the Partial Reference Count Contour Machine, implements the retention strategy. For a large subset of the lifetime well-stacking programs, those that run correctly on the first model, the two models are shown to require nearly the same order of magnitude of time. The use of full label values is shown to have a detrimental effect on the time efficiency of the latter model. Part 1, in Volume 7, Number 1, of this journal, gives a general description of the machines, some of their definitions, and proof of the results. Part 2, in this issue, serves as an appendix to Part 1 and contains most of the formal definitions of the machines.