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

StateGoalSelection

data class StateGoalSelection(val context: ClassicExecutionContext) : AbstractState

"Goal Selection", the entry point of every resolution step: decides what to do with ClassicExecutionContext.goals. Three cases: no goals left and no parent context -> emit the current substitution as a solution and move to StateEnd; no goals left but a parent exists -> pop the stack, carrying the child's substitution (filtered down to variables the parent still cares about, via ClassicExecutionContext.isVariableInteresting) into the parent, and loop back into StateGoalSelection for the parent's remaining goals; goals remain -> move to StatePrimitiveSelection (after recording the current goal's variables as relevant, if TrackVariables is ON).

Constructors

StateGoalSelection

constructor(context: ClassicExecutionContext)

Properties

context

open override val context: ClassicExecutionContext

The execution context this state operates on.

isEndState

open val isEndState: Boolean

Whether this state is a terminal one for the current resolution step, 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: ClassicExecutionContext = this.context): StateGoalSelection

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.