State

State

A State represents an atomic execution unit within a StateMachine. A state becomes active when entered through a transition and remains active until another transition causes the state machine to advance to a different state.

States may be classified as:

• Initial states, which define the starting control state of the containing state machine.
• Terminal states, which indicate completion of the state machine lifecycle.
• Intermediate states, which represent ordinary operational control states.

At any point during execution, exactly one state within a state machine is active.

State behavior is defined through transitions and lifecycle actions:

• On transitions react to incoming events.
• Always transitions are evaluated independently of events and may trigger autonomously when their guard conditions hold.
• Entry actions execute when entering the state.
• Exit actions execute when leaving the state.
• During actions execute while the state remains active.
• After actions define time-triggered behavior through scheduled timeout actions.

States may also declare statically scoped data. Unlike transient data, static data persists across repeated activations of the same state, enabling local state retention between exits and re-entries.

new State {
  initial = true
  terminal = false
  entry {
    new ...Action { ... }
    ...
  }
  exit {
    new ...Action { ... }
    ...
  }
  during {
    new ...Action { ... }
    ...
  }
  after {
    new TimeoutAction { ... }
    ...
  }
  on {
    ["event"] = new Transition { ... }
    ...
  }
  always {
    new Transition { ... }
    ...
  }
  static = new Context { ... }
}

Properties

Property	Type	Multiplicity	Description
initial	Boolean	Optional	Marks the state as the initial state of the containing state machine.
terminal	Boolean	Optional	Marks the state as a terminal state.
entry	List<Action>	Optional	Actions executed upon entering the state.
exit	List<Action>	Optional	Actions executed upon exiting the state.
during	List<Action>	Optional	Actions executed while the state remains active.
after	List<TimeoutAction>	Optional	Time-triggered actions executed while the state is active.
on	Map<String, Transition>	Optional	Event-triggered transitions indexed by event name.
always	List<Transition>	Optional	Transitions evaluated independently of incoming events.
static	Context	Optional	Lexically scoped static data associated with the state.

Name

The name of a state is defined by its key within the enclosing states declaration of the containing state machine.

State names may be used for diagnostics, transition references, runtime inspection, or visualization purposes.

Name Validity

Name validity and naming constraints are implementation-specific.

initial

The initial property specifies whether the state is the initial state of the containing state machine.

An initial state defines the starting control state activated when the state machine instance begins execution.

Constraint: Single Initial State

Exactly one initial state must be declared within a state machine.

Constraint: Initial State Reachability

Initial states must not declare inward transitions.

terminal

The terminal property specifies whether the state is terminal.

Terminal states indicate completion of the containing state machine lifecycle. Multiple terminal states may sexist within the same state machine.

Constraint: Terminal State Finality

Terminal states must not declare outward transitions.

entry, exit, during, after

Lifecycle actions define executable behavior associated with the state.

• entry actions execute when the state becomes active.
• exit actions execute immediately before leaving the state.
• during actions execute while the state remains active.
• after actions define timeout-triggered behavior evaluated during state execution.

Actions execute within the lexical scope of the state and have access to all variables visible through the CSM scoping hierarchy. See Data Model.

on

The on property defines event-driven transitions originating from the state.

Each entry associates an incoming event with a transition specification. When a matching event is received and the transition guard evaluates to true, the transition becomes enabled.

Events may originate from:

• The containing state machine
• Other state machines
• External systems or devices
• Runtime-generated timeout events

Constraint: Valid Event References

Events referenced by on transitions must correspond to valid events observable within the collaborative state machine execution context.

always

The always property defines spontaneous transitions evaluated independently of incoming events.

Always transitions enable autonomous control progression based on guard evaluation and internal execution semantics.

These transitions correspond to event-independent execution semantics within the CSM model.

static

The static property declares lexically scoped static data associated with the state.

Static data persists across repeated activations of the same state and retains its values after exiting and re-entering the state.