Halim Djerroud

S-Planner is a fast symbolic planner written in C++17, designed to be modular and explainable. It takes a PDDL domain and a PDDL problem as command-line arguments, parses them through a Flex/Bison front-end, and solves them by classical heuristic forward search — no SAT encoding, no LP backend, no translation to a generic solver. The supported PDDL fragment covers typed STRIPS extended with negative preconditions, conditional effects (when), and universal and existential quantifiers (forall, exists) — essentially the ADL subset minus disjunctive preconditions. States are encoded as bitsets and manipulated with word-level bit operations, which keeps the inner loop tight: the relaxed-plan heuristics (h_add, h_max, h_ff) and the search algorithms (A*, GBFS, BFS) all operate directly on these compact state representations. Distributed under GPL-3, developed at LISV (UVSQ / Paris-Saclay).