Full Indexing for Lazy Narrowing

W. Hans, H. Kuchen, St. Winkler

	   Indexing improves the efficiency of many logic programs
	   considerably.  Here, we present a new indexing scheme
	   for a functional logic language which has lazy narrowing
	   as operational semantics. The main difficulty is that the
	   arguments of a function may be unevaluated and that the indexer
	   has to incrementally initiate the evaluation of the arguments
	   to head normal form, if this is required for the selection of
	   a rule. Moreover, each argument has to be evaluated as early
	   as possible in order to avoid re-evaluations of arguments
	   due to backtracking.