Method: RDF::Queryable#first_subject

Defined in:

lib/rdf/mixin/queryable.rb

#first_subject ⇒ RDF::Resource #first_subject(pattern) ⇒ RDF::Resource

Queries ‘self` for an RDF statement matching the given `pattern` and returns the statement’s subject term.

Returns ‘nil` if no statements match `pattern`.

Overloads:

• #first_subject ⇒ RDF::Resource

  Returns:

  • (RDF::Resource)
• #first_subject(pattern) ⇒ RDF::Resource

  Parameters:

  • pattern (RDF::Query, RDF::Statement, Array(RDF::Term), Hash)

  Returns:

  • (RDF::Resource)

Since:

• 0.1.9

# File 'lib/rdf/mixin/queryable.rb', line 216

def first_subject(pattern = nil)
  __send__(*(pattern ? [:query, pattern] : [:each])) do |statement|
    return statement.subject
  end
  return nil
end