class RDF::N3::Algebra::Log::Includes
The subject formula includes the object formula.
Formula
A includes formula B if there exists some substitution which when applied to B creates a formula B’ such that for every statement in B’ is also in A, every variable universally (or existentially) quantified in B’ is quantified in the same way in A.
Variable substitution is applied recursively to nested compound terms such as formulae, lists and sets.
(Understood natively by cwm when in in the antecedent of a rule. You can use this to peer inside nested formulae.)
Constants
- NAME
- URI
Public Instance Methods
Creates a repository constructed by substituting variables and in that subject with known IRIs and queries object against that repository. Either retuns a single solution, or no solutions.
@note this does allow object to have variables not in the subject, if they could have been substituted away.
@param [RDF::N3::Algebra::Formula] subject
a formula
@param [RDF::N3::Algebra::Formula] object
a formula
@return [RDF::Literal::Boolean]
# File lib/rdf/n3/algebra/log/includes.rb, line 40 def apply(subject, object) subject_var_map = subject.variables.values.inject({}) {|memo, v| memo.merge(v => RDF::URI(v.name))} object_vars = object.variables.keys log_debug(NAME, "subject var map") {SXP::Generator.string(subject_var_map.to_sxp_bin)} log_debug(NAME, "object vars") {SXP::Generator.string(object_vars.to_sxp_bin)} # create a queryable from subject, replacing variables with IRIs for thsoe variables. queryable = RDF::Repository.new do |r| log_depth do subject.each do |stmt| parts = stmt.to_quad.map do |part| part.is_a?(RDF::Query::Variable) ? subject_var_map.fetch(part) : part end r << RDF::Statement.from(parts) end end end # Query object against subject solns = log_depth {queryable.query(object, **@options)} log_info("(#{NAME} solutions)") {SXP::Generator.string solns.to_sxp_bin} if !solns.empty? && (object_vars - solns.variable_names).empty? # Return solution solns.first else # Return false, RDF::Literal::FALSE end end
Both subject and object are inputs.
# File lib/rdf/n3/algebra/log/includes.rb, line 26 def input_operand RDF::N3::List.new(values: operands) end
Both subject and object must be formulae.
@param [RDF::Term] resource @param [:subject, :object] position @return [RDF::Term] @see RDF::N3::ResourceOperator#evaluate
# File lib/rdf/n3/algebra/log/includes.rb, line 21 def resolve(resource, position:) resource if resource.formula? end