Standardize Markup::Heading

Author: vinistock

lib/rdoc/markup/heading.rb

@@ -1,84 +1,101 @@
 # frozen_string_literal: true
-##
-# A heading with a level (1-6) and text
 
-RDoc::Markup::Heading =
-  Struct.new :level, :text do
-
-  @to_html = nil
-  @to_label = nil
-
-  ##
-  # A singleton RDoc::Markup::ToLabel formatter for headings.
-
-  def self.to_label
-    @to_label ||= RDoc::Markup::ToLabel.new
-  end
-
-  ##
-  # A singleton plain HTML formatter for headings.  Used for creating labels
-  # for the Table of Contents
-
-  def self.to_html
-    return @to_html if @to_html
-
-    markup = RDoc::Markup.new
-    markup.add_regexp_handling RDoc::CrossReference::CROSSREF_REGEXP, :CROSSREF
-
-    @to_html = RDoc::Markup::ToHtml.new nil
-
-    def @to_html.handle_regexp_CROSSREF(target)
-      target.text.sub(/^\\/, '')
+module RDoc
+  class Markup
+    # A heading with a level (1-6) and text
+    #
+    #  RDoc syntax:
+    #   = Heading 1
+    #   == Heading 2
+    #   === Heading 3
+    #
+    #  Markdown syntax:
+    #   # Heading 1
+    #   ## Heading 2
+    #   ### Heading 3
+    class Heading < Element
+      #: String
+      attr_reader :text
+
+      #: Integer
+      attr_accessor :level
+
+      # A singleton RDoc::Markup::ToLabel formatter for headings.
+      #: () -> RDoc::Markup::ToLabel
+      def self.to_label
+        @to_label ||= Markup::ToLabel.new
+      end
+
+      # A singleton plain HTML formatter for headings. Used for creating labels for the Table of Contents
+      #: () -> RDoc::Markup::ToHtml
+      def self.to_html
+        @to_html ||= begin
+          markup = Markup.new
+          markup.add_regexp_handling CrossReference::CROSSREF_REGEXP, :CROSSREF
+
+          to_html = Markup::ToHtml.new nil
+
+          def to_html.handle_regexp_CROSSREF(target)
+            target.text.sub(/^\\/, '')
+          end
+
+          to_html
+        end
+      end
+
+      #: (Integer, String) -> void
+      def initialize(level, text)
+        super()
+
+        @level = level
+        @text = text
+      end
+
+      #: (Object) -> bool
+      def ==(other)
+        other.is_a?(Heading) && other.level == @level && other.text == @text
+      end
+
+      # @override
+      #: (untyped) -> void
+      def accept(visitor)
+        visitor.accept_heading(self)
+      end
+
+      # An HTML-safe anchor reference for this header.
+      #: () -> String
+      def aref
+        "label-#{self.class.to_label.convert text.dup}"
+      end
+
+      # Creates a fully-qualified label which will include the label from +context+. This helps keep ids unique in HTML.
+      #: (RDoc::Context?) -> String
+      def label(context = nil)
+        label = +""
+        label << "#{context.aref}-" if context&.respond_to?(:aref)
+        label << aref
+        label
+      end
+
+      # HTML markup of the text of this label without the surrounding header element.
+      #: () -> String
+      def plain_html
+        no_image_text = text
+
+        if matched = no_image_text.match(/rdoc-image:[^:]+:(.*)/)
+          no_image_text = matched[1]
+        end
+
+        self.class.to_html.to_html(no_image_text)
+      end
+
+      # @override
+      #: (PP) -> void
+      def pretty_print(q)
+        q.group 2, "[head: #{level} ", ']' do
+          q.pp text
+        end
+      end
     end
-
-    @to_html
-  end
-
-  ##
-  # Calls #accept_heading on +visitor+
-
-  def accept(visitor)
-    visitor.accept_heading self
-  end
-
-  ##
-  # An HTML-safe anchor reference for this header.
-
-  def aref
-    "label-#{self.class.to_label.convert text.dup}"
   end
-
-  ##
-  # Creates a fully-qualified label which will include the label from
-  # +context+.  This helps keep ids unique in HTML.
-
-  def label(context = nil)
-    label = aref
-
-    label = [context.aref, label].compact.join '-' if
-      context and context.respond_to? :aref
-
-    label
-  end
-
-  ##
-  # HTML markup of the text of this label without the surrounding header
-  # element.
-
-  def plain_html
-    text = self.text.dup
-
-    if matched = text.match(/rdoc-image:[^:]+:(.*)/)
-      text = matched[1]
-    end
-
-    self.class.to_html.to_html(text)
-  end
-
-  def pretty_print(q) # :nodoc:
-    q.group 2, "[head: #{level} ", ']' do
-      q.pp text
-    end
-  end
-
 end