Element-access regions for index-aware dependency tracking (Play portion B1; drives the reactive table editor where editing C{5,2} must recompute only the formulas reading that cell).
engine.hpp
environment.hpp
fusion_rule.hpp
lexer.hpp
parser.hpp
play_manifest.hpp
Play manifest extraction (NK Play, portion A).
reactive_session.hpp
ReactiveSession — incremental re-evaluation of a linear script (Play portion B2; also the engine core for the future reactive table editor).