Finite-Tree Analysis for Constraint Logic-Based Languages

Abstract. Logic languages based on the theory of rational, possibly infinite, trees have much appeal in that rational trees allow for faster unification (due to the omission of the occurs-check) and increased expressivity. Note that cyclic terms can provide a very efficient representation of grammars and other useful objects. 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. Moreover, some widelyused program analysis and manipulation techniques are only correct for those parts of programs working over finite trees. It is thus important to obtain, automatically, a knowledge of those program variables (the finite variables) that, at the program points of interest, will always be bound to finite terms. For these reasons, we propose here a new data-flow analysis that captures such information. We presen...

• Type: Conference
• Year: 2001
• Where: SAS
• Authors: Roberto Bagnara, Roberta Gori, Patricia M. Hill, Enea Zaffanella
• Keywords: Formal Methods, Infinite Rational Trees, Rational Trees, SAS 2001, finite Variables