Class: SPARQL::Algebra::Operator::Triple

Inherits:
Operator::Ternary
  • Object
show all
Includes:
Evaluatable
Defined in:
lib/sparql/algebra/operator/triple.rb

Overview

Note:

This operator overlaps with RDF::Query::Pattern as used as an operand to a BGP.

The SPARQL triple operator.

If the 3-tuple (term1, term2, term3) is an RDF-star triple, the function returns this triple. If the 3-tuple is not an RDF-star triple, then the function raises an error.

[121] BuiltInCall ::= ... | 'TRIPLE' '(' Expression ',' Expression ',' Expression ')'

Examples:

SPARQL Grammar

PREFIX : <http://example.com/ns#>
SELECT * {
  ?s ?p ?o .
  BIND(TRIPLE(?s, ?p, ?o) AS ?t1)
}

SSE

(prefix ((: <http://example.com/ns#>))
 (extend ((?t1 (triple ?s ?p ?o)))
  (bgp (triple ?s ?p ?o))))

See Also:

Constant Summary collapse

NAME = 
:triple

Instance Method Summary collapse

Methods included from Evaluatable

#evaluate, #memoize, #replace_aggregate!, #replace_vars!

Instance Method Details

#apply(subject, predicate, object, **options) ⇒ RDF::URI

Parameters:

Returns:

  • (RDF::URI)

Raises:

  • (TypeError) —

    if the operand is not a simple literal



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# File 'lib/sparql/algebra/operator/triple.rb', line 35

def apply(subject, predicate, object, **options)
  triple = RDF::Statement(subject, predicate, object)
  raise TypeError, "valid components, but got #{triple.inspect}" unless triple.valid?
  triple
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/triple.rb', line 46

def to_sparql(**options)
  "TRIPLE(#{operands.to_sparql(delimiter: ', ', **options)})"
end