A Precise Type Analysis of Logic Programs
Lunjin Lu
To appear at the 2nd International Conference on Principles and Practice of
Declarative Programming (PPDP 2000), Montreal, Canada, September 20-22, 2000
Abstract
This paper presents a new type analysis for logic programs. The type
information in a set of substitutions is described by a disjunction of
variable typings each of which maps a variable to a non-deterministic
regular type. The use of non-deterministic regular types, set union and
intersection operators, and disjunctions of variable typings makes the
new type analysis more precise than those found in the literature.
Experimental results on the performance of the new analysis are given
together with comparable results from an existing type analysis. The
fundamental problem of checking the emptiness of non-deterministic regular
types is more complex in the new analysis. The experimental results,
however, show that careful use of tabling reduces the effect to an
average of 15% of execution time on a set of benchmarks.