Action

Invoke

An Invoke action calls an external service type, delegating processing, I/O operations, or hardware interactions. It specifies a contract regarding inputs, outputs, and expected functionality rather than a particular implementation.

The runtime system resolves execution placement and can select from multiple implementation variants based on context. Input parameters are passed declaratively using input expressions. Output data is mapped back to the state machine's accessible context variables. Upon completion, conditional events can be evaluated and emitted asynchronously to trigger subsequent state transitions. Co-locating a state machine instance with a local service can reduce communication overhead.

new Invoke {
  type = "serviceType"
  mode = "remote"
  input = new Context { ... }
  output {
    "faceCount"
    "positions"
  }
  emits {
    new ConditionalEvent {
      provided = "faceCount > 5"
      event = new Event { topic = "alert" }
    }
  }
}

Properties

Property	Type	Multiplicity	Description
type	InvocationType	Required	Specifies the requested service type name.
mode	InvocationMode	Optional	Explicitly dictates execution placement ("local" or "remote"). Defaults to "remote".
input	Context	Optional	A map of parameter names to value expressions passed as input data.
output	Listing<VariableName>	Optional	An ordered listing of variable names mapping outputs to accessible context variables.
emits	Listing<ConditionalEvent>	Optional	Conditional event descriptions evaluated and raised upon invocation completion.

type

The type property defines the service type name targeted by the invocation.

Service Binding

Service type validation and binding rules are implementation-specific.

mode

The mode property provides deployment routing guidance to the underlying runtime system. Setting mode = "local" forces the runtime system to execute the targeted computation locally on the same physical host as the state machine instance whenever feasible.

input

The input property maps data parameters into expressions evaluated against the active variable scope at the moment of invocation.

output

The output property specifies destination variables within the state machine's hierarchy.

Constraint: Scope Accessibility

Target variable targets resolved via output listings must comply with upward-only containment rules and reside inside local, static, or persistent contexts.

emits

The emits property allows event-driven continuation by evaluating predicates against returning service context data and dispatching subsequent events accordingly.

Eval

An Eval action evaluates an explicit mathematical, logical, or functional string expression to update state variables within the accessible variable scope.

new Eval {
  expression = "++var"
}

Properties

Property	Type	Multiplicity	Description
expression	Expression	Required	The expression string evaluated to manipulate runtime context values.

Emit

An Emit action creates and publishes an asynchronous event to facilitate reactive interaction among distributed state machines or external systems.

new Emit {
  event = new Event {
    topic = "release"
    channel = "external"
    data = new Context { ["id"] = "id" }
  }
  target = "arbitrator"
}

Properties

Property	Type	Multiplicity	Description
event	EventDescription	Required	Explicit structural layout definition detailing topic channels and parameters.
target	Expression	Optional	Evaluated expression string indicating a unique recipient instance identifier.

target

The optional target keyword explicitly designates a destiny for an emitted event.

Timeout

A Timeout action schedules a future execution trigger. Configured inside the after structural block of control states, it specifies a delay expression that fires an Emit action upon expiration.

new Timeout {
  delay = "10"
  triggers = new Emit {
    event = new Internal { topic = "ate" }
  }
}

Properties

Property	Type	Multiplicity	Description
delay	Expression	Required	The timeout delay in milliseconds.
triggers	EmitDescription	Required	The emit action executed upon timeout.

delay

Constraint: Numerical Evaluation

The delay expression must evaluate down cleanly into valid numeric or time units at runtime.

Reset

A Reset action cancels pending timeouts based on a timeout name.

new Reset {
  name = "timeout"
}

Properties

Property	Type	Multiplicity	Description
name	TimeoutName	Required	Reference text key selecting the targeted timeout to deactivate.

Match

A Match action evaluates sequential logical guard predicates over application data elements to establish conditional execution. It provides structured branch selection across an array of Case blocks alongside an optional fallback default.

new Match {
  cases = new Listing {
    new Case {
      of = "expression"
      yields {
        new ...Action { ... }
        ...
      }
    }
    ...
  }
  default = new ...Action { ... }
}

Properties

Property	Type	Multiplicity	Description
cases	Listing<CaseDescription>	Required	An ordered array containing conditional branches to assess sequentially.
default	ActionDescription	Optional	A fallback action block triggered if all preceding guard tests fail.

Log

A Log action provides formatting primitives for text monitoring, profiling metrics, and diagnostic tracking.

new Log {
  message = "'Message'"
}

Properties

Property	Type	Multiplicity	Description
message	Expression	Required	String expression output.

Instantiate

An Instantiate action dynamically spawns new, parameterized instances of state machine classes at runtime.

new Instantiate {
  instances {
    ["name"] = new InstanceDescription {
      stateMachineName = "stateMachine"
      data = new Context { ... }
    }
    ...
  }
}

Properties

Property	Type	Multiplicity	Description
instances	Mapping<DynamicInstanceName, Instance>	Required	A mapping block tracking the keys and initialization profiles of new dynamic components.