Returns a Solution equivalent to this one, but with every variable not occurring in query (nor bound, in substitution, to a variable occurring in query) removed from substitution. Useful to drop resolution-internal variables before presenting a solution to a user.

containsTag

open fun containsTag(name: String): Boolean

copy

abstract fun copy(query: Struct = this.query, exception: ResolutionException = this.exception): Solution.Halt

Returns a Halt solution identical to this one, except for the explicitly-provided arguments.

getTag

open fun <T : Any> getTag(name: String): T?

replaceTags

abstract override fun replaceTags(tags: Map<String, Any>): Solution.Halt

valueOf

abstract fun valueOf(variable: Var): Term?

Returns the Term bound to variable in substitution, or null if variable is unbound (or this is not a Yes solution).

abstract fun valueOf(variable: String): Term?

Same as valueOf, but looking variable up by name rather than by Var instance.

whenIs

open fun <T> whenIs(yes: (Solution.Yes) -> T? = null, no: (Solution.No) -> T? = null, halt: (Solution.Halt) -> T? = null, otherwise: (Solution) -> T = { throw IllegalStateException("Cannot handle solution $it") }): T

Exhaustively (or partially) pattern-matches this Solution against its three possible subtypes, invoking whichever of yes/no/halt corresponds to this solution's actual kind, or otherwise if that branch was left null (by default, throwing IllegalStateException).