solve/it.unibo.tuprolog.solve.flags/Unknown

Unknown

object Unknown : NotableFlag

The ISO Prolog unknown flag, controlling what happens when a goal's predicate does not exist in the current knowledge base/libraries at all: raise an it.unibo.tuprolog.solve.exception.error.ExistenceError (ERROR, the default), just report a it.unibo.tuprolog.solve.exception.warning.MissingPredicate warning (WARNING), or silently fail the goal (FAIL).

Properties

admissibleValues

open override val admissibleValues: Sequence<Term>

Every legal value this flag may take.

open override val defaultValue: Term

The value this flag takes unless explicitly set otherwise.

val ERROR: Atom

Raise an it.unibo.tuprolog.solve.exception.error.ExistenceError for missing predicates.

Silently fail the goal for missing predicates.

open val isEditable: Boolean

Whether this flag's value can be changed at all (false for e.g. MaxArity).

open override val name: String

This flag's name, as it appears as the key in a FlagStore (e.g. "unknown", "double_quotes").

val WARNING: Atom

Warn (via it.unibo.tuprolog.solve.exception.warning.MissingPredicate) about missing predicates instead of raising an error.

Functions

isAdmissibleValue

open fun isAdmissibleValue(value: Term): Boolean

Whether value is one of admissibleValues.

open infix fun to(value: Term): Pair<String, Term>

This flag's name paired with value, ready to be inserted into a FlagStore.

open fun toPair(): Pair<String, Term>

This flag's name paired with its defaultValue, ready to be inserted into a FlagStore.