Combining an improvement to PARMA trailing with trailing analysis
Tom Schrijvers, Bart Demoen · 2002
Trailing of bindings in the PARMA variable representation is expensive in time and space. Two schemes are presented that lower its cost: the first is a technique that halves the space cost of trailing in PARMA. It can be used with conditional and unconditional trailing. It is illustrated and evaluated in the context of dProlog and in the Mercury backend of HAL. The second scheme combines a variant of a previously developed trailing analysis with the first technique. Empirical evidence shows the usefulness of these schemes and that the combination is more effective than each scheme apart.