Add Term#terms and Statement#terms which returns an array including itself, and array including the non-nil non-statement terms, respectively.

Author: gkellogg

README.md

@@ -7,7 +7,7 @@ This is a pure-Ruby library for working with [Resource Description Framework
 
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 [![Gitter chat](https://badges.gitter.im/ruby-rdf/rdf.png)](https://gitter.im/ruby-rdf/rdf)
 
 ## Features

etc/n-triples-star.ebnf

@@ -0,0 +1,7 @@
+[1] ntriplesDoc ::= triple? (EOL triple)* EOL?
+[2] triple      ::= subject predicate object '.'
+[3] subject     ::= IRIREF | BLANK_NODE_LABEL | embTriple
+[4] predicate   ::= IRIREF
+[5] object      ::= IRIREF | BLANK_NODE_LABEL | literal | embTriple
+[6] literal     ::= STRING_LITERAL_QUOTE ('^^' IRIREF | LANGTAG)?
+[7] embTriple   ::= '<<' subject predicate object '>>'

etc/n-triples.ebnf

@@ -0,0 +1,6 @@
+[1] ntriplesDoc ::= triple? (EOL triple)* EOL?
+[2] triple      ::= subject predicate object '.'
+[3] subject     ::= IRIREF | BLANK_NODE_LABEL
+[4] predicate   ::= IRIREF
+[5] object      ::= IRIREF | BLANK_NODE_LABEL | literal
+[6] literal     ::= STRING_LITERAL_QUOTE ('^^' IRIREF | LANGTAG)?

lib/rdf/mixin/enumerable.rb

@@ -511,7 +511,7 @@ def enum_object
     def terms(unique: true)
       unless unique
         enum_statement.
-          map(&:to_quad).
+          map(&:terms).
           flatten.
           compact
       else
@@ -551,8 +551,8 @@ def each_term
       if block_given?
         values = {}
         each_statement do |statement|
-          statement.to_quad.each do |value|
-            unless value.nil? || values.include?(value.hash)
+          statement.terms.each do |value|
+            unless values.include?(value.hash)
               values[value.hash] = true
               yield value
             end

lib/rdf/model/statement.rb

@@ -240,7 +240,8 @@ def has_object?
     end
 
     ##
-    # Returns `true` if any resource of this statement is a blank node.
+    # Returns `true` if any resource of this statement is a blank node
+    # or has an embedded statement including a blank node.
     #
     # @return [Boolean]
     # @since 2.0
@@ -359,6 +360,13 @@ def to_triple
     end
     alias_method :to_a, :to_triple
 
+    ##
+    # Returns an array of all the non-nil non-statement terms.
+    # @return [Array(RDF::Term)]
+    def terms
+      to_quad.map {|t| t.respond_to?(:terms) ? t.terms : t}.flatten.compact
+    end
+
     ##
     # Canonicalizes each unfrozen term in the statement
     #

lib/rdf/model/term.rb

@@ -72,6 +72,14 @@ def to_term
       self
     end
 
+    ##
+    # Returns an array including just itself.
+    #
+    # @return [Array<RDF::Value>]
+    def terms
+      [self]
+    end
+
     ##
     # Returns the base representation of this term.
     #

spec/model_statement_spec.rb

@@ -75,6 +75,7 @@
     it {is_expected.not_to be_quoted}
     it {is_expected.to be_statement}
     it {is_expected.not_to be_inferred}
+    its(:terms) {is_expected.to include(s, p, o)}
   end
 
   context "when created with a blank node subject" do
@@ -116,6 +117,12 @@
     specify {expect(RDF::Statement(:s, p, o)).to eql (RDF::Statement(:s, p, o))}
     specify {expect(RDF::Statement(s, p, :o)).to eq (RDF::Statement(s, p, :o))}
     specify {expect(RDF::Statement(s, p, :o)).to eql (RDF::Statement(s, p, :o))}
+
+    describe "#terms" do
+      subject {RDF::Statement(:s, p, o)}
+      specify {expect(subject.terms).not_to include(:s)}
+      specify {expect(subject.terms).to include(p, o)}
+    end
   end
 
   context "when used with strings" do
@@ -293,6 +300,14 @@
     it "is embedded for statements having a statement object" do
       expect(RDF::Statement(:s, :p, RDF::Statement(:s1, :p1, :o1))).to be_embedded
     end
+
+    context "#terms" do
+      let(:s1) {RDF::URI.new("http://example.org/s1")}
+      let(:p1) {RDF::URI("http://example.org/p1")}
+      let(:o1) {RDF::URI.new("http://example.org/o1")}
+      subject {RDF::Statement(s, p, RDF::Statement(s1, p1, o1))}
+      specify {expect(subject.terms).to include(s, p, s1, p1, o1)}
+    end
   end
 
   context "c14n" do

spec/model_term_spec.rb

@@ -22,6 +22,11 @@
     is_expected.to be_term
   end
 
+  its(:terms) do
+    is_expected.to be_a(Array)
+    is_expected.to eq [subject]
+  end
+
   it "#to_term" do
     expect(subject.to_term).to equal subject
   end