Class: RDF::N3::Algebra::Log::Semantics

Inherits:
ResourceOperator show all
Defined in:
vendor/bundler/ruby/3.3.0/bundler/gems/rdf-n3-a6ef81a7e1ce/lib/rdf/n3/algebra/log/semantics.rb

Overview

The log:semantics of a document is the formula. achieved by parsing representation of the document. For a document in Notation3, log:semantics is the log:parsedAsN3 of the log:contents of the document. For a document in RDF/XML, it is parsed according to the RDF/XML specification to yield an RDF formula (a subclass of N3 log:Formula).

[Aside: Philosophers will be distracted here into worrying about the meaning of meaning. At least we didn't call this function "meaning"! In as much as N3 is used as an interlingua for interoperability for different systems, this for an N3 based system is the meaning expressed by a document.]

(Cwm knows how to go get a document and parse N3 and RDF/XML it in order to evaluate this. Other languages for web documents may be defined whose N3 semantics are therefore also calculable, and so they could be added in due course. See for example GRDDL, RDFa, etc)

Constant Summary collapse

NAME = 
:logSemantics
URI = 
RDF::N3::Log.semantics

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

Constants included from SPARQL::Algebra::Expression

SPARQL::Algebra::Expression::PATTERN_PARENTS

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 inherited from ResourceOperator

#as_literal, #execute, #input_operand, #valid?

Methods included from Builtin

#each, #evaluate, #hash, #input_operand, #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, #canonicalize, #canonicalize!, #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?, #graph_names, #invalid?, #method_missing, #object?, #objects, #predicate?, #predicates, #project_graph, #quad?, #quads, #respond_to_missing?, #statement?, #statements, #subject?, #subjects, #supports?, #term?, #terms, #to_a, #to_h, #to_set, #triple?, #triples, #valid?, #validate!

Methods included from Util::Aliasing::LateBound

#alias_method

Methods included from Isomorphic

#bijection_to, #isomorphic_with?

Methods included from Countable

#count, #empty?

Methods included from SPARQL::Algebra::Update

#execute, #graph_name=, #unshift, #variables

Methods included from SPARQL::Algebra::Query

#each_solution, #empty?, #execute, #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_sparql, to_sparql, #to_sxp, #to_sxp_bin, #validate!, #variable?, #variables, #vars

Methods included from SPARQL::Algebra::Expression

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

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

Parses the subject into a new formula.

Returns nil if resource does not validate, given its position

Parameters:

Returns:



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# File 'vendor/bundler/ruby/3.3.0/bundler/gems/rdf-n3-a6ef81a7e1ce/lib/rdf/n3/algebra/log/semantics.rb', line 19

def resolve(resource, position: :subject)
  case position
  when :subject
    return nil unless resource.literal? || resource.uri?
    begin
      repo = RDF::N3::Repository.new
      repo << RDF::Reader.open(resource, **@options.merge(list_terms: true, base_uri: resource, logger: false))
      content_hash = repo.statements.hash # used as name of resulting formula
      form = RDF::N3::Algebra::Formula.from_enumerable(repo, graph_name: RDF::Node.intern(content_hash))
      log_debug(NAME) {"form hash (#{resource}): #{form.hash}"}
      form
    rescue IOError, RDF::ReaderError => e
      log_error(NAME) {"error loading #{resource}: #{e}"}
      nil
    end
  when :object
    return nil unless resource.literal? || resource.variable?
    resource
  end
end