Class: SPARQL::Algebra::Operator::SameTerm

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

Overview

The SPARQL sameTerm operator.

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

Examples:

SPARQL Grammar

PREFIX     :    <http://example.org/things#>
SELECT * {
  ?x1 :p ?v1 .
  ?x2 :p ?v2 .
  FILTER sameTerm(?v1, ?v2)
}

SSE

(prefix
 ((: <http://example.org/things#>))
 (filter (sameTerm ?v1 ?v2)
  (bgp (triple ?x1 :p ?v1) (triple ?x2 :p ?v2))))

See Also:

Constant Summary collapse

NAME = 
:sameTerm

Instance Method Summary collapse

Methods included from Evaluatable

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

Instance Method Details

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

Returns true if the operands are the same RDF term; returns false otherwise.

Parameters:

Returns:

  • (RDF::Literal::Boolean) —

    true or false

Raises:

  • (TypeError) —

    if either operand is unbound



38
39
40
 
# File 'lib/sparql/algebra/operator/same_term.rb', line 38

def apply(term1, term2, **options)
  RDF::Literal(term1.eql?(term2))
end

#optimize(**options) ⇒ SameTerm

Returns an optimized version of this expression.

Return true if variable operand1 is a bound variable and equals operand2

Returns:

See Also:



49
50
51
52
53
54
55
 
# File 'lib/sparql/algebra/operator/same_term.rb', line 49

def optimize(**options)
  if operand(0).is_a?(Variable) && operand(0).bound? && operand(0).eql?(operand(1))
    RDF::Literal::TRUE
  else
    super # @see Operator#optimize!
  end
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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

def to_sparql(**options)
  "sameTerm(#{operands.to_sparql(delimiter: ', ', **options)})"
end