Class: SPARQL::Algebra::Operator::Abs

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

Overview

The SPARQL logical abs operator.

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

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT * WHERE {
  ?s :num ?num
  FILTER(ABS(?num) >= 2)
}

SSE

(prefix ((: <http://example.org/>))
 (filter (>= (abs ?num) 2)
  (bgp (triple ?s :num ?num))))

See Also:

Constant Summary collapse

NAME = 
[:abs]

Instance Method Summary collapse

Methods included from Evaluatable

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

Instance Method Details

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

Returns the absolute value of arg. An error is raised if arg is not a numeric value.

Parameters:

  • operand (RDF::Literal) —

    the operand

Returns:

  • (RDF::Literal) —

    literal of same type

Raises:

  • (TypeError) —

    if the operand is not a numeric value



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# File 'lib/sparql/algebra/operator/abs.rb', line 34

def apply(operand, **options)
  case operand
    when RDF::Literal::Numeric then operand.abs
    else raise TypeError, "expected an RDF::Literal::Numeric, but got #{operand.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/abs.rb', line 46

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