Schematic rules within unfold/fold approach to program transformation

Some classes of transformations (e.g., conversion to tall recursion) are more naturally expressed using schematic rules. These schematic rules can be represented within functional languages by higher-order functions (c.f. schemes) together with an extended language feature, called guarded constraint. How such schematic rules can be created and utilized within an unfold/fold transformation system is outlined. To apply these schematic rules, the authors also propose a matching technique, based on transformation, to match specific functions to generic higher-order ones. An exploration is also conducted of the possibility of applying an explanation-based generalization technique to obtain more widely applicable schematic rules from single transformation instances