MASS4.Graph.State 1.2.0

MASS4.Graph.State

State machines over the core graph model. Depends only on MASS4.Graph; boolean guards and state outputs compose with data evaluation through IDataPlane.

Registration and execution

Call StateNodes.Register(registry) to register state-flow ports, built-in entry/state/transition node types, trigger/priority annotations and the built-in transition migration. StateSemantics binds those built-ins by default. Bind domain types through AddEntry, AddState and AddTransition; one type has one state role. IsEntry, TryGetState and TryGetTransition report the bindings.

A machine requires one connected entry node, and each transition must join two states. Cycles and self-transitions are legal. Each instance stores its current state, time in state, raised triggers and behavior memory. A tick takes at most one transition and then clears triggers; higher priorities are checked first, with transition node identity breaking ties. The interpreter gets tick duration from the required StateTime host feature. StateContext and TransitionContext wrap a StateFrame; StateMachineProgram is the interpreter's frame and generated backends supply their own.

Signals, payloads and migrations

Triggers are registered SignalType identities in GraphTypeRegistry.Signals; old identities resolve through the same registry's rename entries. Set a transition's trigger and priority with StateNodes.Annotations(trigger, priority), passing the SignalType declaration rather than its identity. StateGraphBuilder adds typed entry, state and transition nodes (AddTransition(editor, from.Exit, to.Enter, signal, priority)) as atomic edits, and hosts raise with graph.Raise(instances, instance, signal). Edits and loads both store a renamed signal under its current identity; names never take part in resolution. These are compile-time annotations; the machine checks the trigger before the transition behavior runs. Custom evaluation payloads such as a timer duration remain independent of those annotations.

StateNodes.CreateGuardedTransition creates a version 2 transition with a boolean condition input. Hand-written registrations must also call StateNodes.AddTransitionMigration(registry, domainType.Id): it lifts version 1 trigger/priority payloads into annotations. Generated guarded declarations emit this migration automatically. A domain's custom payload migration remains explicit; the legacy State migration must not strip unrelated evaluation payloads.

Use Rules during editing and check compilation diagnostics for machine completeness. MG3001–MG3007 cover flow roles, signals, entry/transition wiring and misplaced annotations. Missing migrations preserve old data and report a diagnostic.

See the guard FSM sample and migration/composition tests.