Class: RDF::N3::Reader

Inherits:
Reader
  • Object
show all
Includes:
EBNF::LL1::Parser, Terminals, Util::Logger
Defined in:
lib/rdf/n3/reader.rb

Overview

TODO:

A Notation-3/Turtle parser in Ruby

N3 Parser, based in librdf version of predictiveParser.py Separate pass to create branch_table from n3-selectors.n3

This implementation only supports quickVars at the document scope.

Non-distinguished blank node variables are created as part of reasoning.

  • Formulae as RDF::Query representations

  • Formula expansion similar to SPARQL Construct

See Also:

Author:

Defined Under Namespace

Classes: Recovery, SyntaxError

Constant Summary

Constants included from Terminals

Terminals::ANON, Terminals::BASE, Terminals::BLANK_NODE_LABEL, Terminals::DECIMAL, Terminals::DOUBLE, Terminals::ECHAR, Terminals::ESCAPE_CHAR4, Terminals::ESCAPE_CHAR8, Terminals::EXPONENT, Terminals::INTEGER, Terminals::IPLSTART, Terminals::IRIREF, Terminals::IRI_RANGE, Terminals::LANGTAG, Terminals::PERCENT, Terminals::PLX, Terminals::PNAME_LN, Terminals::PNAME_NS, Terminals::PN_CHARS, Terminals::PN_CHARS_BASE, Terminals::PN_CHARS_BODY, Terminals::PN_CHARS_U, Terminals::PN_LOCAL, Terminals::PN_LOCAL_BODY, Terminals::PN_LOCAL_ESC, Terminals::PN_PREFIX, Terminals::PREFIX, Terminals::QUICK_VAR_NAME, Terminals::STRING_LITERAL_LONG_QUOTE, Terminals::STRING_LITERAL_LONG_SINGLE_QUOTE, Terminals::STRING_LITERAL_QUOTE, Terminals::STRING_LITERAL_SINGLE_QUOTE, Terminals::UCHAR, Terminals::U_CHARS1, Terminals::U_CHARS2, Terminals::WS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input = $stdin, **options) {|reader| ... } ⇒ reader

Initializes the N3 reader instance.

Parameters:

  • input (IO, File, String) (defaults to: $stdin) —

    the input stream to read

  • options (Hash) —

    a customizable set of options

Options Hash (**options):

  • :base_uri (#to_s) — default: nil —

    the base URI to use when resolving relative URIs (not supported by all readers)

  • :validate (Boolean) — default: false —

    whether to validate the parsed statements and values

  • :canonicalize (Boolean) — default: false —

    whether to canonicalize parsed literals and URIs.

  • :prefixes (Hash) — default: Hash.new —

    the prefix mappings to use (not supported by all readers)

  • :list_terms (Hash) — default: false —

    represent collections as an ‘RDF::Term`, rather than an rdf:first/rest ladder.

Yields:

  • (reader) —

    ‘self`

Yield Parameters:

  • reader (RDF::Reader)

Yield Returns:

  • (void) —

    ignored

Raises:

  • (Error) —

    Raises RDF::ReaderError if validating and an error is found



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# File 'lib/rdf/n3/reader.rb', line 83

def initialize(input = $stdin, **options, &block)
  super do
    @options = {
      anon_base:  "b0",
      whitespace:  WS,
      depth: 0,
    }.merge(@options)
    @prod_stack = []

    @formulae = []
    @formula_nodes = {}
    @label_uniquifier = "0"
    @bnodes = {}
    @bn_labler = @options[:anon_base].dup
    @bn_mapper = {}
    @variables = {}

    if options[:base_uri]
      progress("base_uri") { base_uri.inspect}
      namespace(nil, iri(base_uri.to_s.match?(%r{[#/]$}) ? base_uri : "#{base_uri}#"))
    end

    # Prepopulate operator namespaces unless validating
    unless validate?
      namespace(:rdf, RDF.to_uri)
      namespace(:rdfs, RDF::RDFS.to_uri)
      namespace(:xsd, RDF::XSD.to_uri)
      namespace(:crypto, RDF::N3::Crypto.to_uri)
      namespace(:list, RDF::N3::List.to_uri)
      namespace(:log, RDF::N3::Log.to_uri)
      namespace(:math, RDF::N3::Math.to_uri)
      namespace(:rei, RDF::N3::Rei.to_uri)
      #namespace(:string, RDF::N3::String.to_uri)
      namespace(:time, RDF::N3::Time.to_uri)
    end
    progress("validate") {validate?.inspect}
    progress("canonicalize") {canonicalize?.inspect}

    @lexer = EBNF::LL1::Lexer.new(input, self.class.patterns, **@options)

    if block_given?
      case block.arity
        when 0 then instance_eval(&block)
        else block.call(self)
      end
    end
  end
end

Instance Attribute Details

#formula_nodes ⇒ Hash{RDF::Node => RDF::Graph} (readonly)

All nodes allocated to formulae

Returns:



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# File 'lib/rdf/n3/reader.rb', line 40

def formula_nodes
  @formula_nodes
end

#formulae ⇒ Array<RDF::Node> (readonly)

Nodes used as Formulae graph names

Returns:



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# File 'lib/rdf/n3/reader.rb', line 35

def formulae
  @formulae
end

#variables ⇒ Hash{Symbol => RDF::Node} (readonly)

Allocated variables by formula

Returns:



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# File 'lib/rdf/n3/reader.rb', line 45

def variables
  @variables
end

Class Method Details

.options ⇒ Object

N3 Reader options

See Also:



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# File 'lib/rdf/n3/reader.rb', line 50

def self.options
  super + [
    RDF::CLI::Option.new(
      symbol: :list_terms,
      datatype: TrueClass,
      default: true,
      control: :checkbox,
      on: ["--list-terms CONTEXT"],
      description: "Use native collections (lists), not first/rest ladder.")
  ]
end

Instance Method Details

#each_statement {|statement| ... } ⇒ void

This method returns an undefined value.

Iterates the given block for each RDF statement in the input.

Yields:

  • (statement)

Yield Parameters:



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# File 'lib/rdf/n3/reader.rb', line 141

def each_statement(&block)
  if block_given?
    log_recover
    @callback = block

    begin
      while (@lexer.first rescue true)
        read_n3Doc
      end
    rescue EBNF::LL1::Lexer::Error, SyntaxError, EOFError, Recovery
      # Terminate loop if EOF found while recovering
    end

    if validate? && log_statistics[:error]
      raise RDF::ReaderError, "Errors found during processing"
    end
  end
  enum_for(:each_statement)
end

#each_triple {|subject, predicate, object| ... } ⇒ void

This method returns an undefined value.

Iterates the given block for each RDF triple in the input.

Yields:

  • (subject, predicate, object)

Yield Parameters:

  • subject (RDF::Resource)
  • predicate (RDF::URI)
  • object (RDF::Value) 


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# File 'lib/rdf/n3/reader.rb', line 169

def each_triple
  if block_given?
    each_statement do |statement|
      yield(*statement.to_triple)
    end
  end
  enum_for(:each_triple)
end

#inspect ⇒ Object 



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# File 'lib/rdf/n3/reader.rb', line 132

def inspect
  sprintf("#<%s:%#0x(%s)>", self.class.name, __id__, base_uri.to_s)
end