Class: SPARQL::Algebra::Operator::Subtract

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

Overview

The SPARQL numeric subtract operator.

[116] AdditiveExpression ::= MultiplicativeExpression ( '-' MultiplicativeExpression )?

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT ?s WHERE {
  ?s :p ?o .
  ?s2 :p ?o2 .
  FILTER(?o - ?o2 = 3) .
}

SSE

(prefix
 ((: <http://example.org/>))
 (project (?s)
  (filter (= (- ?o ?o2) 3)
   (bgp
    (triple ?s :p ?o)
    (triple ?s2 :p ?o2)))))

See Also:

Constant Summary collapse

NAME = 
[:-, :subtract]

Instance Method Summary collapse

Methods included from Evaluatable

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

Instance Method Details

#apply(left, right, **options) ⇒ RDF::Literal::Numeric, ...

Returns the arithmetic difference of the operands.

Parameters:

  • left (RDF::Literal::Numeric, RDF::Literal::Temporal) —

    a numeric literal

  • right (RDF::Literal::Numeric, RDF::Literal::Temporal, RDF::Literal::Duration) —

    a numeric literal

Returns:

  • (RDF::Literal::Numeric, RDF::Literal::Temporal, RDF::Literal::Duration)

Raises:

  • (TypeError) —

    if either operand is neither a numeric nor a temporal literal



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# File 'lib/sparql/algebra/operator/subtract.rb', line 40

def apply(left, right, **options)
  case
    when left.is_a?(RDF::Literal::Numeric) && right.is_a?(RDF::Literal::Numeric)
      left - right
    when left.is_a?(RDF::Literal::Temporal) && right.is_a?(RDF::Literal::Temporal)
      left - right
    when left.is_a?(RDF::Literal::Temporal) && right.is_a?(RDF::Literal::Duration)
      left - right
    else raise TypeError, "expected two RDF::Literal::Numeric, Temporal operands, or a Temporal and a Duration, but got #{left.inspect} and #{right.inspect}"
  end
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/subtract.rb', line 57

def to_sparql(**options)
  "(#{operands.first.to_sparql(**options)} - #{operands.last.to_sparql(**options)})"
end