solve-classic/it.unibo.tuprolog.solve.classic.fsm/StateHalt

StateHalt

data class StateHalt(val exception: ResolutionException, val context: ClassicExecutionContext) : AbstractEndState, ExceptionalState

"Halt": the one true sink of the state machine, reached only via an uncaught exception (no catch/3 matched it all the way up to the root context, or a timeout occurred). Unlike StateEnd, there is no transition back out of it -- resolution truly stops here, with Solution.halt wrapping exception.

Constructors

StateHalt

constructor(exception: ResolutionException, context: ClassicExecutionContext)

Properties

context

open override val context: ClassicExecutionContext

The execution context this state operates on.

exception

open override val exception: ResolutionException

The exception that led to this state.

hasOpenAlternatives

open val hasOpenAlternatives: Boolean

Whether asking for another solution after this one would resume resolution (via backtracking) rather than truly stop.

isEndState

open override val isEndState: Boolean

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

solution

open override val solution: Solution

The solution emitted by reaching this state.

Functions

asEndState

open override 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: ClassicExecutionContext = this.context): StateHalt

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

open override fun next(): State

Computes the state the machine transitions into from here -- a pure function of context.