solve-streams/it.unibo.tuprolog.solve.streams/SolverStrategies

SolverStrategies

The pluggable choice points of :solve-streams' resolution engine: given a Sequence of candidates, which one does the solver commit to first, and when is a goal considered proven?

Every StreamsExecutionContext carries one SolverStrategies instance (defaulting to prologStandard), and the internal state-machine states (StateGoalEvaluation, StateRuleSelection, ...) consult it -- together with it.unibo.tuprolog.solve.streams.solver.orderWithStrategy -- whenever they need to order candidate predications/clauses or decide whether a term counts as a successful demonstration.

Because :solve-streams currently exposes no public constructor parameter (on StreamsSolverFactory or elsewhere) to inject a custom SolverStrategies into a it.unibo.tuprolog.solve.Solver instance, this interface is, at present, effectively fixed to prologStandard from outside this module.

Author

Enrico

Types

Companion

object Companion

Functions

clauseChoiceStrategy

abstract fun <C : Clause> clauseChoiceStrategy(unifiableClauses: Sequence<C>, context: ExecutionContext): C

Selects, from unifiableClauses, the clause that should be expanded in place of the current predication.

predicationChoiceStrategy

abstract fun <P : Term> predicationChoiceStrategy(predicationSequence: Sequence<P>, context: ExecutionContext): P

Selects, from predicationSequence, the predication that should be solved first.

successCheckStrategy

abstract fun successCheckStrategy(term: Term, context: ExecutionContext): Boolean

Determines whether term -- the result of a resolution step in context -- counts as a successful demonstration.