Class: RDF::N3::Algebra::ResourceOperator

Inherits:
SPARQL::Algebra::Operator::Binary show all
Includes:
Builtin, SPARQL::Algebra::Query, SPARQL::Algebra::Update
Defined in:
vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb

Overview

This is a generic operator where the subject is a literal or binds to a literal and the object is either a constant that equals the evaluation of the subject, or a variable to which the result is bound in a solution

Constant Summary collapse

NAME =
:resourceOperator

Constants included from Util::Logger

Util::Logger::IOWrapper

Constants inherited from SPARQL::Algebra::Operator::Binary

SPARQL::Algebra::Operator::Binary::ARITY

Constants inherited from SPARQL::Algebra::Operator

SPARQL::Algebra::Operator::ARITY, SPARQL::Algebra::Operator::IsURI, SPARQL::Algebra::Operator::URI

Instance Attribute Summary

Attributes included from Enumerable

#existentials, #universals

Attributes included from SPARQL::Algebra::Query

#solutions

Attributes inherited from SPARQL::Algebra::Operator

#operands

Instance Method Summary collapse

Methods included from Builtin

#each, #evaluate, #hash, #rank, #to_uri

Methods included from Util::Logger

#log_debug, #log_depth, #log_error, #log_fatal, #log_info, #log_recover, #log_recovering?, #log_statistics, #log_warn, #logger

Methods included from Enumerable

add_entailment, #dump, #each_graph, #each_object, #each_predicate, #each_quad, #each_statement, #each_subject, #each_term, #each_triple, #entail, #enum_graph, #enum_object, #enum_predicate, #enum_quad, #enum_statement, #enum_subject, #enum_term, #enum_triple, #graph_names, #has_graph?, #has_object?, #has_predicate?, #has_quad?, #has_statement?, #has_subject?, #has_term?, #has_triple?, #invalid?, #method_missing, #objects, #predicates, #project_graph, #quads, #respond_to_missing?, #statements, #subjects, #supports?, #terms, #to_a, #to_h, #to_set, #triples, #validate!

Methods included from Util::Aliasing::LateBound

#alias_method

Methods included from Countable

#count, #empty?

Methods included from Isomorphic

#bijection_to, #isomorphic_with?

Methods included from SPARQL::Algebra::Update

#graph_name=, #unshift, #variables

Methods included from SPARQL::Algebra::Query

#each_solution, #empty?, #failed?, #graph_name=, #matched?, #query_yields_boolean?, #query_yields_solutions?, #query_yields_statements?, #unshift, #variables

Methods inherited from SPARQL::Algebra::Operator::Binary

#initialize

Methods inherited from SPARQL::Algebra::Operator

#aggregate?, arity, base_uri, #base_uri, base_uri=, #bind, #boolean, #constant?, #deep_dup, #each_descendant, #eql?, #evaluatable?, evaluate, #executable?, #first_ancestor, for, #formulae, #initialize, #inspect, #ndvars, #node?, #operand, #optimize, #optimize!, #parent, #parent=, #prefixes, prefixes, prefixes=, #rewrite, #to_binary, #to_sxp, #to_sxp_bin, #validate!, #variable?, #vars

Methods included from SPARQL::Algebra::Expression

cast, #constant?, #evaluate, extension, extensions, for, #invalid?, new, #node?, open, #optimize, #optimize!, parse, register_extension, #to_sxp_bin, #validate!, #variable?

Constructor Details

This class inherits a constructor from SPARQL::Algebra::Operator::Binary

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class RDF::Enumerable

Instance Method Details

#as_literal(object) ⇒ Object

Returns a literal for the numeric argument.



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# File 'vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb', line 112

def as_literal(object)
  case object
  when Float
    literal = RDF::Literal(object, canonicalize: true)
    literal.instance_variable_set(:@string, literal.to_s.downcase)
    literal
  else
    RDF::Literal(object, canonicalize: true)
  end
end

#execute(queryable, solutions:, **options) ⇒ RDF::Query::Solutions

The operator takes a literal and provides a mechanism for subclasses to operate over (and validate) that argument.

Parameters:

Returns:



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# File 'vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb', line 19

def execute(queryable, solutions:, **options)
  RDF::Query::Solutions(solutions.map do |solution|
    subject = operand(0).evaluate(solution.bindings, formulae: formulae) || operand(0)
    object = operand(1).evaluate(solution.bindings, formulae: formulae) || operand(1)
    subject = formulae.fetch(subject, subject) if subject.node?
    object = formulae.fetch(object, object) if object.node?

    log_info(self.class.const_get(:NAME), "subject") {SXP::Generator.string(subject.to_sxp_bin).strip}
    log_info(self.class.const_get(:NAME), "object") {SXP::Generator.string(object.to_sxp_bin).strip}
    next unless valid?(subject, object)

    lhs = resolve(subject, position: :subject)
    if lhs.nil?
      log_error(self.class.const_get(:NAME), "subject evaluates to null") {subject.inspect}
      next
    end

    rhs = resolve(object, position: :object)
    if rhs.nil?
      log_error(self.class.const_get(:NAME), "object evaluates to null") {object.inspect}
      next
    end

    if object.variable?
      log_debug(self.class.const_get(:NAME), "result") {SXP::Generator.string(lhs.to_sxp_bin).strip}
      solution.merge(object.to_sym => lhs)
    elsif subject.variable?
      log_debug(self.class.const_get(:NAME), "result") {SXP::Generator.string(rhs.to_sxp_bin).strip}
      solution.merge(subject.to_sym => rhs)
    elsif respond_to?(:apply)
      res = apply(lhs, rhs)
      log_debug(self.class.const_get(:NAME), "result") {SXP::Generator.string(res.to_sxp_bin).strip}
      # Return the result applying subject and object
      #require 'byebug'; byebug
      case res
      when RDF::Literal::TRUE
        solution
      when RDF::Literal::FALSE
        nil
      when RDF::Query::Solution
        solution.merge(res)
      else
        log_error(self.class.const_get(:NAME), "unexpected result type")
        nil
      end
    elsif rhs != lhs
      log_debug(self.class.const_get(:NAME), "result: false")
      nil
    else
      log_debug(self.class.const_get(:NAME), "result: true")
      solution
    end
  end.compact.uniq)
end

#input_operandRDF::Term

Input is generically the subject

Returns:



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# File 'vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb', line 78

def input_operand
  operand(0)
end

#resolve(resource, position: :subject) ⇒ RDF::Term

Subclasses implement resolve.

Returns nil if resource does not validate, given its position

Parameters:

Returns:

Raises:



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# File 'vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb', line 89

def resolve(resource, position: :subject)
  raise NotImplemented
end

#valid?(subject, object) ⇒ Boolean

Subclasses may override or supplement validate to perform validation on the list subject

Parameters:

Returns:

  • (Boolean)


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# File 'vendor/bundler/ruby/2.7.0/bundler/gems/rdf-n3-8f30bf85f229/lib/rdf/n3/algebra/resource_operator.rb', line 99

def valid?(subject, object)
  case subject
  when RDF::Query::Variable
    object.term?
  when RDF::Term
    object.term? || object.variable?
  else
    false
  end
end