Class: SPARQL::Algebra::Operator::Divide

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

Overview

The SPARQL numeric divide operator.

[117] MultiplicativeExpression::= UnaryExpression ( '' UnaryExpression | '/' UnaryExpression )

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT ?s WHERE {
  ?s :p ?o .
  ?s2 :p ?o2 .
  FILTER(?o / ?o2 = 4) .
}

SSE

(prefix ((: <http://example.org/>))
 (project (?s)
  (filter (= (/ ?o ?o2) 4)
   (bgp
    (triple ?s :p ?o)
    (triple ?s2 :p ?o2)))))

See Also:

Constant Summary collapse

NAME = 
[:'/', :divide]

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 quotient of the operands.

Parameters:

  • left (RDF::Literal::Numeric) —

    a numeric literal

  • right (RDF::Literal::Numeric) —

    a numeric literal

Returns:

  • (RDF::Literal::Numeric)

Raises:

  • (TypeError) —

    if either operand is not a numeric literal



39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
 
# File 'lib/sparql/algebra/operator/divide.rb', line 39

def apply(left, right, **options)
  case
    when left.is_a?(RDF::Literal::Numeric) && right.is_a?(RDF::Literal::Numeric)
      # For xsd:decimal and xsd:integer operands, if the divisor is
      # (positive or negative) zero, an error is raised.
      raise ZeroDivisionError, "divided by #{right}" if left.is_a?(RDF::Literal::Decimal) && right.zero?

      # As a special case, if the types of both operands are
      # xsd:integer, then the return type is xsd:decimal.
      if left.is_a?(RDF::Literal::Integer) && right.is_a?(RDF::Literal::Integer)
        RDF::Literal(left.to_d / right.to_d)
      else
        left / right
      end
    else raise TypeError, "expected two RDF::Literal::Numeric operands, but got #{left.inspect} and #{right.inspect}"
  end
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


62
63
64
 
# File 'lib/sparql/algebra/operator/divide.rb', line 62

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