Tabled execution in Scheme (Scheme Pearl)

Jeremiah Willcock, Andrew Lumsdaine, Daniel Quinlan

Tabled execution is a generalization of memoization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.
LLNL-ABS-405521. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The project 07-ERD-057 was funded by the Laboratory Directed Research and Development Program at LLNL.

Last updated 23 July 2008.

Valid XHTML 1.0!