Boolean Functions for Finite-Tree Dependencies

Several logic-based languages, such as Prolog II and its successors, SICStus Prolog and Oz, offer a computation domain including rational trees. Infinite rational trees allow for increased expressivity (cyclic terms can provide efficient representations of grammars and other useful objects) and for faster unification (due to the safe omission of the occurscheck). Unfortunately, the use of infinite rational trees has problems. For instance, many of the built-in and library predicates are ill-defined for such trees and need to be supplemented by run-time checks whose cost may be significant. In a companion paper [3] we have proposed a dataflow analysis aimed at the knowledge of those program variables (the finite variables) that will always be bound to finite terms. The analysis domain introduced in [3] correctly captures the creation and propagation of cyclic terms, but is not capable of propagating the guarantees of finiteness that come from built-in predicates and program a...

• Type: Conference
• Year: 2001
• Where: LPAR
• Authors: Roberto Bagnara, Enea Zaffanella, Roberta Gori, Patricia M. Hill
• Keywords: Automated Reasoning, Cyclic Terms, Infinite Rational Trees, LPAR 2001, Rational Trees