Struct RdfFusionExprBuilderContext 

pub struct RdfFusionExprBuilderContext<'context> { /* private fields */ }

An expression builder for creating SPARQL expressions.

This is the builder context, which can be used to create expression builders. Each builder context has an associated schema. This schema is used for, for example, inferring the type of built expressions and is therefore crucial.

Furthermore, the context holds a reference to an RdfFusionFunctionRegistry that is used to resolve the registered built-ins and user-defined functions.

Implementations

impl<'context> RdfFusionExprBuilderContext<'context>

pub fn new( rdf_fusion_context: &'context RdfFusionContextView, schema: &'context DFSchema, ) -> RdfFusionExprBuilderContext<'context>

Creates a new expression builder context.

pub fn schema(&self) -> &DFSchema

Returns the schema of the input data.

pub fn rdf_fusion_context(&self) -> &RdfFusionContextView

Returns a reference to the RDF Fusion context.

pub fn registry(&self) -> &dyn RdfFusionFunctionRegistry

Returns a reference to the used function registry.

pub fn encodings(&self) -> &'context RdfFusionEncodings

Returns a reference to the used object id encoding.

pub fn try_create_builder( &self, expr: Expr, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a new RdfFusionExprBuilder from an existing Expr.

pub fn try_create_builder_for_udf( &self, name: &FunctionName, args: Vec<Expr>, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a new RdfFusionExprBuilder from an existing Expr.

pub fn coalesce( &self, args: Vec<Expr>, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a new expression that evaluates to the first argument that does not produce an error.

Relevant Resources

• SPARQL 1.1 - Coalesce

pub fn bnode(&self) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that generates a new blank node.

Relevant Resources

• SPARQL 1.1 - BNODE

pub fn uuid(&self) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that computes a fresh IRI from the urn:uuid: scheme.

Relevant Resources

• SPARQL 1.1 - UUID

pub fn str_uuid( &self, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that computes a string literal representation of a UUID.

Relevant Resources

• SPARQL 1.1 - STRUUID

pub fn concat( &self, args: Vec<Expr>, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that concatenates the string representations of its arguments.

Relevant Resources

• SPARQL 1.1 - CONCAT

pub fn rand(&self) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that computes a pseudo-random value between 0 and 1.

The data type of the value is xsd:double.

Relevant Resources

• SPARQL 1.1 - Rand

pub fn variable( &self, variable: VariableRef<'_>, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression from a SPARQL variable.

If the variable is not bound in the current context (i.e., not in the schema), the expression evaluates to a null literal.

pub fn literal<'lit>( &self, term: impl Into<TermRef<'lit>>, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a literal expression from an RDF term.

The term is encoded using the PlainTermEncoding.

pub fn null_literal( &'context self, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a null literal expression.

This is used to represent unbound variables or errors.

pub fn exists( self, exists_plan: LogicalPlan, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a new exists filter operator. This operator takes another graph pattern (as a LogicalPlan) that is checked against the current graph pattern. Only solutions that have at least one compatible solution in the EXISTS graph pattern pass this filter.

Relevant Resources

• SPARQL 1.1 - NOT EXISTS and EXISTS

pub fn not_exists( self, exists_plan: LogicalPlan, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a new not exists filter operator. This operator takes another graph pattern (as a LogicalPlan) that is checked against the current graph pattern. Only solutions that have no compatible solution in the EXISTS graph pattern pass this filter.

Relevant Resources

• SPARQL 1.1 - NOT EXISTS and EXISTS

pub fn native_int64_as_term( &self, expr: Expr, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that converts a native i64 value into an RDF term.

This is done by encoding the literal and calling BuiltinName::NativeInt64AsTerm.

pub fn native_boolean_as_term( &self, expr: Expr, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates an expression that converts a native boolean value into an RDF term.

This is done by encoding the literal and calling BuiltinName::NativeBooleanAsTerm.

pub fn and( &self, lhs: Expr, rhs: Expr, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a SPARQL logical AND expression.

This differs from a standard AND by its error treatment.

Relevant Resources

• SPARQL 1.1 - Logical-and
• SPARQL 1.1 - Filter Evaluation

pub fn sparql_or( self, lhs: Expr, rhs: Expr, ) -> Result<RdfFusionExprBuilder<'context>, DataFusionError>

Creates a SPARQL logical OR expression.

This differs from a standard OR by its error treatment.

Relevant Resources

• SPARQL 1.1 - Logical-or
• SPARQL 1.1 - Filter Evaluation

Trait Implementations

impl<'context> Clone for RdfFusionExprBuilderContext<'context>

fn clone(&self) -> RdfFusionExprBuilderContext<'context>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'context> Debug for RdfFusionExprBuilderContext<'context>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'context> Copy for RdfFusionExprBuilderContext<'context>