solve/it.unibo.tuprolog.solve.primitive/BinaryRelation

BinaryRelation

abstract class BinaryRelation<E : ExecutionContext>(operator: String) : PrimitiveWrapper<E>

Base class to implement primitives that relate two Terms and provide a single response, sparing implementers from manually pulling first/second out of Solve.Request.arguments and checking the request's arity (always 2, enforced by PrimitiveWrapper).

This class and its nested subclasses form a ladder of increasingly specific (and increasingly convenient) template methods to override, from most to least general:

BinaryRelation itself -- override computeAll for a fully backtrackable relation producing arbitrarily many Solve.Responses (including side effects), e.g. via Solve.Request.replyWith;
WithoutSideEffects -- override computeAllSubstitutions for a backtrackable relation with no side effects, producing a Sequence of Substitutions (one per solution);
NonBacktrackable -- override computeOne for a deterministic relation (no choice points) still able to attach side effects to its single Solve.Response;
Functional -- override computeOneSubstitution for a deterministic, side-effect-free relation producing a single Substitution;
Predicative -- override compute for a deterministic, pure test returning true/false (e.g. ==/2).

See the it.unibo.tuprolog.solve.stdlib.primitive implementations (e.g. arithmetic comparisons) for concrete examples of each level.

Inheritors

WithoutSideEffects

NonBacktrackable

AbstractGetData

Constructors

BinaryRelation

constructor(operator: String)

Types

Functional

abstract class Functional<E : ExecutionContext>(operator: String) : BinaryRelation.NonBacktrackable<E>

A NonBacktrackable that only needs to produce a single Substitution, without custom side effects.

NonBacktrackable

abstract class NonBacktrackable<E : ExecutionContext>(operator: String) : BinaryRelation<E>

A BinaryRelation known to be deterministic, i.e. producing exactly one Solve.Response (no choice points).

Predicative

abstract class Predicative<E : ExecutionContext>(operator: String) : BinaryRelation.NonBacktrackable<E>

A NonBacktrackable that is a pure success/failure test, with no substitution nor side effects.

WithoutSideEffects

abstract class WithoutSideEffects<E : ExecutionContext>(operator: String) : BinaryRelation<E>

A BinaryRelation that only needs to produce the Substitutions for each solution, without custom side effects.

Properties

descriptionPair

val descriptionPair: Pair<Signature, Primitive>

Gets this wrapped primitive description Pair formed by signature and wrapped primitive type

functor

val functor: String

A shorthand to get the signature functor name

implementation

override val implementation: Primitive

Checked primitive implementation

signature

val signature: Signature