solve-concurrent/it.unibo.tuprolog.solve.concurrent.fsm/StateException

StateException

data class StateException(val exception: ResolutionException, val context: ConcurrentExecutionContext) : AbstractState, ExceptionalState

The state a branch transitions into whenever resolution raises a ResolutionException: for a LogicError, it looks for an enclosing catch/3 goal along ConcurrentExecutionContext.pathToRoot that unifies with the error, and either resumes the branch inside the catcher's recovery goal (StateGoalSelection), or propagates the exception one level up towards the parent context (recursing into another StateException); any other ResolutionException (or a LogicError that reaches an unhandled ConcurrentExecutionContext.isRoot) ends the branch in a StateHalt.

Constructors

StateException

constructor(exception: ResolutionException, context: ConcurrentExecutionContext)

Properties

context

open override val context: ConcurrentExecutionContext

The execution context this state operates on.

exception

open override val exception: ResolutionException

The exception this state needs to propagate/handle.

isEndState

open val isEndState: Boolean

Whether this state is a terminal one for the current branch, i.e. an EndState.

Functions

asEndState

open fun asEndState(): EndState?

This state as an EndState, or null if isEndState is false.

castToEndState

open fun castToEndState(): EndState

This state as an EndState.

clone

open override fun clone(context: ConcurrentExecutionContext = this.context): StateException

Returns a copy of this state, replacing context with the given one (defaulting to the current context).

open override fun next(): Iterable<State>

Computes every state this branch may transition into from here, one per alternative (matching clause, disjunct, primitive solution, ...) available at this point; empty only for EndStates. Each element is meant to be explored independently (and, in :solve-concurrent's solver, concurrently) of the others.