Class ExpressionEngine

A Comunica engine for evaluating SPARQL expressions, without executing queries.

Hierarchy (View Summary)

ExpressionEngineBase
- ExpressionEngine

Index

Constructors

Methods

createAggregator createEvaluator createTermComparator prepareContext

Constructors

constructor

new ExpressionEngine(engine?: ActorInitExpressions): ExpressionEngine
Parameters
- engine: ActorInitExpressions = ...
Returns ExpressionEngine
Overrides ExpressionEngineBase.constructor
- Defined in engines/expressions-sparql/lib/ExpressionEngine.ts:21

Methods

createAggregator

createAggregator(
expression: Algebra.AggregateExpression,
context?: IActionContext,
): Promise<IBindingsAggregator>
Create an aggregator for a SPARQL aggregate expression, such as SUM(?x).
Parameters
- expression: Algebra.AggregateExpression
  The algebra of the aggregate expression.
- Optionalcontext: IActionContext
  An optional context, missing entries are defaulted.
Returns Promise<IBindingsAggregator>
Inherited from ExpressionEngineBase.createAggregator
- Defined in packages/actor-init-expressions/lib/ExpressionEngineBase.ts:38

createEvaluator

createEvaluator(
expression: BaseExpression,
context?: IActionContext,
): Promise<IExpressionEvaluator>
Create an evaluator for a SPARQL expression, such as the expression of a FILTER clause.
Parameters
- expression: BaseExpression
  The algebra of the expression to evaluate.
- Optionalcontext: IActionContext
  An optional context, missing entries are defaulted.
Returns Promise<IExpressionEvaluator>
Inherited from ExpressionEngineBase.createEvaluator
- Defined in packages/actor-init-expressions/lib/ExpressionEngineBase.ts:28

createTermComparator

createTermComparator(context?: IActionContext): Promise<ITermComparator>
Create a comparator that orders RDF terms as ORDER BY does.
Parameters
- Optionalcontext: IActionContext
  An optional context, missing entries are defaulted.
Returns Promise<ITermComparator>
Inherited from ExpressionEngineBase.createTermComparator
- Defined in packages/actor-init-expressions/lib/ExpressionEngineBase.ts:34

`Protected`prepareContext

prepareContext(context?: IActionContext): IActionContext
Default the context entries that every expression evaluator requires. Engines can extend this with defaults that are specific to their configuration.
Parameters
- Optionalcontext: IActionContext
  The context provided by the caller.
Returns IActionContext
Overrides ExpressionEngineBase.prepareContext
- Defined in engines/expressions-sparql/lib/ExpressionEngine.ts:25