Higher-Order Programming in an OR-intensive Style

Because implementations tend to favour a recursive deterministic ANDintensive programming style, it seems counter intuitive that a backtracking findall-based paradigm can be more efficient. This is explained by a source level technique which is called goal precomputation, by a heap-based copyonce findall and optimized meta predicates. A precomputed goal containing a future (reusable) computation is backtracked over instead of being constructed repeatedly. These techniques are enough, in terms of efficiency, to rehabilitate a generator based OR-intensive programming style. On the other side, we will try to find out how to improve the traditional AND-intensive implementation of higher-order primitives and study the impact of meta-programming constructs like call/N. We introduce a new `universal' higher-order predicate implemented also with goal precomputation which combines on the fly selected answers from a generator. By using it for the executable specification of key higher-order Pr..