resolves #2298 add numbering for parts

- number parts using roman numerals if the partnums attribute is set
- move method to convert integer to roman to Helpers module
- assign the value "Part" to the part-refsig attribute by default
- define the part-label attribute in the attributes-en.adoc data file
- add support for partnums and sectnums=all to create_section helper in extensions
- add partnums and sectnums=all scenarios to test for create_section helper

10 files changed, 229 insertions, 50 deletions

diff --git a/data/locale/attributes-en.adoc b/data/locale/attributes-en.adoc
index c4132c37..9457a501 100644
--- a/data/locale/attributes-en.adoc
+++ b/data/locale/attributes-en.adoc
@@ -11,7 +11,8 @@
 ifdef::listing-caption[:listing-caption: Listing]
 //:manname-title: Name
 :note-caption: Note
-:part-refsig: Part
+:part-label: Part
+:part-refsig: {part-label}
 ifdef::preface-title[:preface-title: Preface]
 :section-refsig: Section
 :table-caption: Table
diff --git a/features/xref.feature b/features/xref.feature
index 9a5974ee..bd4215a6 100644
--- a/features/xref.feature
+++ b/features/xref.feature
@@ -263,6 +263,147 @@ Feature: Cross References
     |to find a complete list of features.
     """
 
+  Scenario: Create a full cross reference to a numbered part
+  Given the AsciiDoc source
+    """
+    :doctype: book
+    :sectnums:
+    :partnums:
+    :xrefstyle: full
+
+    [preface]
+    = Preface
+
+    See <<p1>> for an introduction to the language.
+
+    [#p1]
+    = Language
+
+    == Syntax
+
+    This chapter covers the syntax.
+    """
+  When it is converted to html
+  Then the result should contain the HTML structure
+    """
+    |See
+    a<> href='#p1' Part I, &#8220;Language&#8221;
+    |for an introduction to the language.
+    """
+
+  Scenario: Create a short cross reference to a numbered part
+  Given the AsciiDoc source
+    """
+    :doctype: book
+    :sectnums:
+    :partnums:
+    :xrefstyle: short
+
+    [preface]
+    = Preface
+
+    See <<p1>> for an introduction to the language.
+
+    [#p1]
+    = Language
+
+    == Syntax
+
+    This chapter covers the syntax.
+    """
+  When it is converted to html
+  Then the result should contain the HTML structure
+    """
+    |See
+    a<> href='#p1' Part I
+    |for an introduction to the language.
+    """
+
+  Scenario: Create a basic cross reference to a numbered part
+  Given the AsciiDoc source
+    """
+    :doctype: book
+    :sectnums:
+    :partnums:
+    :xrefstyle: basic
+
+    [preface]
+    = Preface
+
+    See <<p1>> for an introduction to the language.
+
+    [#p1]
+    = Language
+
+    == Syntax
+
+    This chapter covers the syntax.
+    """
+  When it is converted to html
+  Then the result should contain the HTML structure
+    """
+    |See
+    a<> href='#p1' Language
+    |for an introduction to the language.
+    """
+
+  Scenario: Create a basic cross reference to an unnumbered part
+  Given the AsciiDoc source
+    """
+    :doctype: book
+    :sectnums:
+    :xrefstyle: full
+
+    [preface]
+    = Preface
+
+    See <<p1>> for an introduction to the language.
+
+    [#p1]
+    = Language
+
+    == Syntax
+
+    This chapter covers the syntax.
+    """
+  When it is converted to html
+  Then the result should contain the HTML structure
+    """
+    |See
+    a<> href='#p1' Language
+    |for an introduction to the language.
+    """
+
+  @wip
+  Scenario: Create a cross reference to a part using a custom chapter reference signifier
+  Given the AsciiDoc source
+    """
+    :doctype: book
+    :sectnums:
+    :partnums:
+    :xrefstyle: full
+    :part-refsig: P
+
+    [preface]
+    = Preface
+
+    See <<p1>> for an introduction to the language.
+
+    [#p1]
+    = Language
+
+    == Syntax
+
+    This chapter covers the syntax.
+    """
+  When it is converted to html
+  Then the result should contain the HTML structure
+    """
+    |See
+    a<> href='#p1' P I, &#8220;Language&#8221;
+    |for an introduction to the language.
+    """
+
   Scenario: Create a full cross reference to a numbered appendix
   Given the AsciiDoc source
     """
diff --git a/lib/asciidoctor/converter/html5.rb b/lib/asciidoctor/converter/html5.rb
index 1bb199d2..5d51e52c 100644
--- a/lib/asciidoctor/converter/html5.rb
+++ b/lib/asciidoctor/converter/html5.rb
@@ -322,11 +322,10 @@ MathJax.Hub.Config({
 
     def section node
       if (level = node.level) == 0
-        title = node.title
         sect0 = true
+        title = node.numbered && level <= (node.document.attr 'sectnumlevels', 3).to_i ? %(#{node.sectnum} #{node.title}) : node.title
       else
-        num = node.numbered && !node.caption && level <= (node.document.attr 'sectnumlevels', 3).to_i ? %(#{node.sectnum} ) : ''
-        title = %(#{num}#{node.captioned_title})
+        title = node.numbered && !node.caption && level <= (node.document.attr 'sectnumlevels', 3).to_i ? %(#{node.sectnum} #{node.title}) : node.captioned_title
       end
       if node.id
         id_attr = %( id="#{id = node.id}")
diff --git a/lib/asciidoctor/document.rb b/lib/asciidoctor/document.rb
index 9e609943..77254e60 100644
--- a/lib/asciidoctor/document.rb
+++ b/lib/asciidoctor/document.rb
@@ -363,7 +363,7 @@ class Document < AbstractBlock
     attrs['toc-title'] = 'Table of Contents'
     #attrs['preface-title'] = 'Preface'
     attrs['section-refsig'] = 'Section'
-    #attrs['part-refsig'] = 'Part'
+    attrs['part-refsig'] = 'Part'
     attrs['chapter-refsig'] = 'Chapter'
     attrs['appendix-caption'] = attrs['appendix-refsig'] = 'Appendix'
     attrs['untitled-label'] = 'Untitled'
diff --git a/lib/asciidoctor/extensions.rb b/lib/asciidoctor/extensions.rb
index 0c9b0cf2..c77b4e54 100644
--- a/lib/asciidoctor/extensions.rb
+++ b/lib/asciidoctor/extensions.rb
@@ -116,16 +116,17 @@ module Extensions
     # Returns a [Section] node with all properties properly initialized.
     def create_section parent, title, attrs, opts = {}
       doc = parent.document
-      doctype, level = doc.doctype, (opts[:level] || parent.level + 1)
+      book = (doctype = doc.doctype) == 'book'
+      level = opts[:level] || parent.level + 1
       if (style = attrs.delete 'style')
-        if style == 'abstract' && doctype == 'book'
+        if book && style == 'abstract'
           sectname, level = 'chapter', 1
         else
           sectname, special = style, true
           level = 1 if level == 0
         end
-      elsif doctype == 'book'
-        sectname = level == 0 ? 'part' : (level == 1 ? 'chapter' : 'section')
+      elsif book
+        sectname = level == 0 ? 'part' : (level > 1 ? 'section' : 'chapter')
       elsif doctype == 'manpage' && (title.casecmp 'synopsis') == 0
         sectname, special = 'synopsis', true
       else
@@ -135,12 +136,20 @@ module Extensions
       sect.title, sect.sectname = title, sectname
       if special
         sect.special = true
-        sect.numbered = true if opts.fetch :numbered, (style == 'appendix')
-      elsif opts.fetch :numbered, (level > 0 && (doc.attributes.key? 'sectnums'))
-        sect.numbered = sect.special ? (parent.context == :section && parent.numbered) : true
+        if opts.fetch :numbered, (style == 'appendix')
+          sect.numbered = true
+        elsif !(opts.key? :numbered) && (doc.attr? 'sectnums', 'all')
+          sect.numbered = book && level == 1 ? :chapter : true
+        end
+      elsif level > 0
+        if opts.fetch :numbered, (doc.attr? 'sectnums')
+          sect.numbered = sect.special ? parent.numbered && true : true
+        end
+      else
+        sect.numbered = true if opts.fetch :numbered, (book && (doc.attr? 'partnums'))
       end
       unless (id = attrs.delete 'id') == false
-        sect.id = attrs['id'] = id || ((doc.attributes.key? 'sectids') ? (Section.generate_id sect.title, doc) : nil)
+        sect.id = attrs['id'] = id || ((doc.attr? 'sectids') ? (Section.generate_id sect.title, doc) : nil)
       end
       sect.update_attributes attrs
       sect
diff --git a/lib/asciidoctor/helpers.rb b/lib/asciidoctor/helpers.rb
index f79b707f..6c4dacbf 100644
--- a/lib/asciidoctor/helpers.rb
+++ b/lib/asciidoctor/helpers.rb
@@ -209,5 +209,22 @@ module Helpers
       end
     end
   end
+
+  ROMAN_NUMERALS = {
+    'M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400, 'C' => 100, 'XC' => 90,
+    'L' => 50, 'XL' => 40, 'X' => 10, 'IX' => 9, 'V' => 5, 'IV' => 4, 'I' => 1
+  }
+
+  # Converts an integer to a Roman numeral.
+  #
+  # val - the [Integer] value to convert
+  #
+  # Returns the [String] roman numeral for this integer
+  def self.int_to_roman val
+    ROMAN_NUMERALS.map {|l, i|
+      repeat, val = val.divmod i
+      l * repeat
+    }.join
+  end
 end
 end
diff --git a/lib/asciidoctor/parser.rb b/lib/asciidoctor/parser.rb
index 36dab24a..114c5fb1 100644
--- a/lib/asciidoctor/parser.rb
+++ b/lib/asciidoctor/parser.rb
@@ -70,11 +70,6 @@ class Parser
     'a' => :asciidoc
   }
 
-  ROMAN_NUMERALS = ::Hash[
-    'M', 1000, 'CM', 900, 'D', 500, 'CD', 400, 'C', 100, 'XC', 90,
-    'L', 50, 'XL', 40, 'X', 10, 'IX', 9, 'V', 5, 'IV', 4, 'I', 1
-  ]
-
   # Public: Make sure the Parser object doesn't get initialized.
   #
   # Raises RuntimeError if this constructor is invoked.
@@ -1533,6 +1528,7 @@ class Parser
   # Returns the section [Block]
   def self.initialize_section reader, parent, attributes = {}
     document = parent.document
+    book = (doctype = document.doctype) == 'book'
     source_location = reader.cursor if document.sourcemap
     sect_style = attributes[1]
     sect_id, sect_reftext, sect_title, sect_level, sect_atx = parse_section_title reader, document, attributes['id']
@@ -1544,26 +1540,23 @@ class Parser
     end
 
     if sect_style
-      if sect_style == 'abstract' && document.doctype == 'book'
+      if book && sect_style == 'abstract'
         sect_name, sect_level = 'chapter', 1
       else
         sect_name, sect_special = sect_style, true
         sect_level = 1 if sect_level == 0
         sect_numbered = sect_style == 'appendix'
       end
-    else
-      case document.doctype
-      when 'book'
-        sect_name = sect_level == 0 ? 'part' : (sect_level == 1 ? 'chapter' : 'section')
-      when 'manpage'
-        if (sect_title.casecmp 'synopsis') == 0
-          sect_name, sect_special = 'synopsis', true
-        else
-          sect_name = 'section'
-        end
+    elsif book
+      sect_name = sect_level == 0 ? 'part' : (sect_level > 1 ? 'section' : 'chapter')
+    elsif doctype == 'manpage'
+      if (sect_title.casecmp 'synopsis') == 0
+        sect_name, sect_special = 'synopsis', true
       else
         sect_name = 'section'
       end
+    else
+      sect_name = 'section'
     end
 
     section = Section.new parent, sect_level, false
@@ -1573,11 +1566,13 @@ class Parser
       if sect_numbered
         section.numbered = true
       elsif document.attributes['sectnums'] == 'all'
-        section.numbered = sect_level == 1 && document.doctype == 'book' ? :chapter : true
+        section.numbered = book && sect_level == 1 ? :chapter : true
       end
-    elsif sect_level > 0 && (document.attributes.key? 'sectnums')
+    elsif document.attributes['sectnums'] && sect_level > 0
       # NOTE a special section here is guaranteed to be nested in another section
       section.numbered = section.special ? parent.numbered && true : true
+    elsif book && sect_level == 0 && document.attributes['partnums']
+      section.numbered = true
     end
 
     # generate an ID if one was not embedded or specified as anchor above section title
@@ -2206,13 +2201,13 @@ class Parser
       marker = 'A.'
     when :lowerroman
       if validate
-        expected = int_to_roman_numeral(ordinal + 1).downcase
+        expected = Helpers.int_to_roman(ordinal + 1).downcase
         actual = marker.chop # remove trailing )
       end
       marker = 'i)'
     when :upperroman
       if validate
-        expected = int_to_roman_numeral(ordinal + 1)
+        expected = Helpers.int_to_roman(ordinal + 1)
         actual = marker.chop # remove trailing )
       end
       marker = 'I)'
@@ -2725,17 +2720,5 @@ class Parser
   def self.sanitize_attribute_name(name)
     name.gsub(InvalidAttributeNameCharsRx, '').downcase
   end
-
-  # Internal: Converts an integer to a Roman numeral.
-  #
-  # value - The integer to convert
-  #
-  # Returns the String Roman numeral for this integer
-  def self.int_to_roman_numeral value
-    ROMAN_NUMERALS.map {|l, i|
-      repeat, value = value.divmod i
-      l * repeat
-    }.join
-  end
 end
 end
diff --git a/lib/asciidoctor/section.rb b/lib/asciidoctor/section.rb
index ffeff65a..1ad20e86 100644
--- a/lib/asciidoctor/section.rb
+++ b/lib/asciidoctor/section.rb
@@ -44,12 +44,12 @@ class Section < AbstractBlock
   # opts     - An optional Hash of options (default: {})
   def initialize parent = nil, level = nil, numbered = true, opts = {}
     super parent, :section, opts
-    if parent && parent != @document
+    if Section === parent
       @level, @special = level || (parent.level + 1), parent.special
     else
       @level, @special = level || 1, false
     end
-    @numbered = numbered && @level > 0
+    @numbered = numbered
     @index = 0
   end
 
@@ -110,7 +110,9 @@ class Section < AbstractBlock
   # Returns the section number as a String
   def sectnum(delimiter = '.', append = nil)
     append ||= (append == false ? '' : delimiter)
-    if @level > 1 && @parent != @document
+    if @level == 0
+      %(#{Helpers.int_to_roman @number}#{append})
+    elsif @level > 1 && Section === @parent
       %(#{@parent.sectnum(delimiter)}#{@number}#{append})
     else
       %(#{@number}#{append})
diff --git a/test/extensions_test.rb b/test/extensions_test.rb
index c9e73420..e7195c6a 100644
--- a/test/extensions_test.rb
+++ b/test/extensions_test.rb
@@ -1241,15 +1241,17 @@ sect::[%s]
         {
           ''                       => ['chapter',  1, false, true, '_section_title'],
           'level=0'                => ['part',     0, false, false, '_section_title'],
+          'level=0,alt'            => ['part',     0, false, true, '_section_title', { 'partnums' => '' }],
           'level=0,style=appendix' => ['appendix', 1, true,  true, '_section_title'],
           'style=appendix'         => ['appendix', 1, true,  true, '_section_title'],
           'style=glossary'         => ['glossary', 1, true,  false, '_section_title'],
+          'style=glossary,alt'     => ['glossary', 1, true,  :chapter, '_section_title', { 'sectnums' => 'all' }],
           'style=abstract'         => ['chapter',  1, false, true, '_section_title'],
           'id=section-title'       => ['chapter',  1, false, true, 'section-title'],
           'id=false'               => ['chapter',  1, false, true, nil]
-        }.each do |attrlist, (expect_sectname, expect_level, expect_special, expect_numbered, expect_id)|
+        }.each do |attrlist, (expect_sectname, expect_level, expect_special, expect_numbered, expect_id, extra_attrs)|
           input = input_tpl % attrlist
-          document_from_string input, :safe => :server
+          document_from_string input, :safe => :server, :attributes => extra_attrs
           assert_equal expect_sectname, sect.sectname
           assert_equal expect_level, sect.level
           assert_equal expect_special, sect.special
diff --git a/test/sections_test.rb b/test/sections_test.rb
index 7ca13906..dfdea842 100644
--- a/test/sections_test.rb
+++ b/test/sections_test.rb
@@ -1354,6 +1354,31 @@ text
       assert_xpath '//h3[@id="_section_2_2"][starts-with(text(), "2.2. ")]', output, 1
     end
 
+    test 'should number parts when doctype is book and partnums attributes is set' do
+      input = <<-EOS
+= Book Title
+:doctype: book
+:sectnums:
+:partnums:
+
+= Language
+
+== Syntax
+
+content
+
+= Processor
+
+== CLI
+
+content
+      EOS
+
+      output = render_string input
+      assert_xpath '//h1[@id="_language"][text() = "I. Language"]', output, 1
+      assert_xpath '//h1[@id="_processor"][text() = "II. Processor"]', output, 1
+    end
+
     test 'blocks should have level' do
       input = <<-EOS
 = Title