  Although heuristic search is one of the most successful approaches to
classical planning, this planning paradigm does not apply straightforwardly to
Generalized Planning (GP). This paper adapts the planning as heuristic search
paradigm to the particularities of GP, and presents the first native heuristic
search approach to GP. First, the paper defines a program-based solution space
for GP that is independent of the number of planning instances in a GP problem,
and the size of these instances. Second, the paper defines the BFGP algorithm
for GP, that implements a best-first search in our program-based solution
space, and that is guided by different evaluation and heuristic functions.
