Class: SPARQL::Algebra::Operator::Timezone

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

Overview

The SPARQL logical timezone operator.

Returns the timezone part of arg as an xsd:dayTimeDuration. Raises an error if there is no timezone.

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

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT ?s (TIMEZONE(?date) AS ?x) WHERE {
  ?s :date ?date
}

SSE

(prefix
 ((: <http://example.org/>))
 (project (?s ?x)
  (extend ((?x (timezone ?date)))
   (bgp (triple ?s :date ?date)))))

See Also:

Constant Summary collapse

NAME = 
:timezone

Instance Method Summary collapse

Methods included from Evaluatable

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

Instance Method Details

#apply(operand, **options) ⇒ RDF::Literal::Temporal

Returns the timezone part of arg as an xsd:dayTimeDuration. Raises an error if there is no timezone.

This function corresponds to fn:timezone-from-dateTime except for the treatment of literals with no timezone.

Parameters:

  • operand (RDF::Literal) —

    the operand

Returns:

  • (RDF::Literal::Temporal)

Raises:

  • (TypeError) —

    if the operand is not a simple literal



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# File 'lib/sparql/algebra/operator/timezone.rb', line 38

def apply(operand, **options)
  raise TypeError, "expected an RDF::Literal::Temporal, but got #{operand.inspect}" unless operand.is_a?(RDF::Literal::Temporal)
  raise TypeError, "literal has no timezone" unless res = operand.timezone
  res
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/timezone.rb', line 49

def to_sparql(**options)
  "TIMEZONE(" + operands.to_sparql(**options) + ")"
end