Class: SPARQL::Algebra::Operator::Equal

Inherits:
Compare
  • Object
show all
Defined in:
lib/sparql/algebra/operator/equal.rb

Overview

The SPARQL relational = (equal) comparison operator.

[114] RelationalExpression ::= NumericExpression ('=' NumericExpression)?

Examples:

SPARQL Grammar

PREFIX  xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX  : <http://example.org/things#>
SELECT  ?x
WHERE { ?x :p ?v . FILTER ( ?v = 1 ) }

SSE

(prefix
 ((xsd: <http://www.w3.org/2001/XMLSchema#>) (: <http://example.org/things#>))
 (project (?x) (filter (= ?v 1) (bgp (triple ?x :p ?v)))))

See Also:

Direct Known Subclasses

NotEqual

Constant Summary collapse

NAME = 
:'='

Instance Method Summary collapse

Methods inherited from Compare

#to_sparql

Methods included from Evaluatable

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

Instance Method Details

#apply(term1, term2, **options) ⇒ RDF::Literal::Boolean

Returns TRUE if term1 and term2 are the same RDF term as defined in Resource Description Framework (RDF): Concepts and Abstract Syntax [CONCEPTS]; produces a type error if the arguments are both literal but are not the same RDF term *; returns FALSE otherwise. term1 and term2 are the same if any of the following is true:

  • term1 and term2 are equivalent IRIs as defined in 6.4 RDF URI References of [CONCEPTS].
  • term1 and term2 are equivalent literals as defined in 6.5.1 Literal Equality of [CONCEPTS].
  • term1 and term2 are the same blank node as described in 6.6 Blank Nodes of [CONCEPTS].

Parameters:

Returns:

  • (RDF::Literal::Boolean) —

    true or false

Raises:

  • (TypeError) —

    if either operand is not an RDF term or operands are not comperable

See Also:

  • RDF::Term#==


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# File 'lib/sparql/algebra/operator/equal.rb', line 39

def apply(term1, term2, **options)
  term1 = term1.dup.extend(RDF::TypeCheck)
  term2 = term2.dup.extend(RDF::TypeCheck)
  RDF::Literal(term1 == term2)
end